National Toxicology Program

National Toxicology Program
https://ntp.niehs.nih.gov/go/5326

TDMS Study 96007-03 Pathology Tables

NTP Experiment-Test: 96007-03         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 09/30/03
Route: GAVAGE                                     TOXIC EQUIVALENCY FACTOR EVALUATION (TCDD)                      Time: 09:06:07

                                                         FINAL # 3 RATS




       Facility:  Battelle Columbus Laboratory

       Chemical CAS #:  1746-01-6

       Lock Date:  06/28/01

       Cage Range:  All

       Reasons For Removal:    25018 Dosing Accident                   25019 Moribund Sacrifice
                               25020 Natural Death                     25021 Terminal Sacrifice

       Removal Date Range:     All

       Treatment Groups:       Include All
































a  Number of animals examined microscopically at site and number of animals with lesion
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)

                                                              Page   1


NTP Experiment-Test: 96007-03         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 09/30/03    
Route: GAVAGE                                     TOXIC EQUIVALENCY FACTOR EVALUATION (TCDD)                      Time: 09:06:07    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         SPRAGUE-DAWLEY RATS FEMALE                   0 NG/KG      3 NG/KG      10 NG/KG     22 NG/KG     46 NG/KG     100          
                                                                                                                       NG/KG        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
                                                                                                                                    
  Animals Initially In Study                          98           98           98           98           98           98           
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                19           27           15           19           17           17           
    Natural Death                                      9            6           10           15           14           15           
    Dosing Accident                                                              5                                                  
  Survivors                                                                                                                         
    Terminal Sacrifice                                25           21           23           19           22           21           
                                                                                                                                    
  Animals Examined Microscopically                    53           54           53           53           53           53           
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Esophagus                                          (52)         (54)         (53)         (52)         (53)         (53)         
      Hemorrhage                                                                 1 [4.0]                                            
      Perforation                                                                2                                                  
      Muscularis, Inflammation                         1 [2.0]      2 [2.5]      1 [2.0]      1 [2.0]      2 [1.5]                  
      Periesophageal Tissue, Inflammation                                        3 [2.7]                                            
   Intestine Large, Colon                             (52)         (53)         (53)         (53)         (53)         (51)         
      Parasite Metazoan                                1            2            1                                      2           
   Intestine Large, Rectum                            (52)         (54)         (53)         (52)         (53)         (53)         
      Parasite Metazoan                                6            4                                      2            1           
   Intestine Small, Duodenum                          (53)         (54)         (53)         (52)         (53)         (53)         
      Cyst                                                                                                              1 [2.0]     
      Ulcer                                                         1 [3.0]                                                         
      Epithelium, Hyperplasia                                                    1 [1.0]                                            
   Liver                                              (53)         (54)         (53)         (53)         (53)         (53)         
      Angiectasis                                      2 [1.5]      1 [1.0]      1 [1.0]                   3 [1.7]      5 [2.0]     
      Basophilic Focus                                 8            6            8            7            3            3           
      Basophilic Focus, Multiple                       4            3            5            1            2            5           
      Cholangiofibrosis                                1 [1.0]      1 [1.0]      2 [1.5]      1 [1.0]     11 [2.5]     31 [2.4]     
      Clear Cell Focus                                 4            1            1            2            1            1           
      Clear Cell Focus, Multiple                       1                                      2            1            1           
      Congestion                                       2 [1.0]                                                          2 [2.0]     
      Cytoplasmic Alteration                                                                                            2 [2.0]     
      Degeneration, Cystic                                                                    2 [1.0]                   4 [2.3]     
      Eosinophilic Focus                               8            6            7           10            5            2           
      Eosinophilic Focus, Multiple                     3            8           14           17           22           42           
      Fatty Change, Diffuse                                         2 [1.0]     12 [1.1]     17 [1.3]     30 [1.2]     48 [1.9]     
      Fatty Change, Focal                              2 [1.5]      6 [1.5]      4 [1.5]      4 [1.8]      1 [1.0]      2 [2.0]     
      Hematopoietic Cell Proliferation                 1 [2.0]      2 [1.0]      2 [1.0]      4 [1.5]      2 [2.0]      2 [2.0]     
      Hemorrhage                                                                                           1 [3.0]                  
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    2                                                              
                                                                                                                                   
NTP Experiment-Test: 96007-03         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 09/30/03    
Route: GAVAGE                                     TOXIC EQUIVALENCY FACTOR EVALUATION (TCDD)                      Time: 09:06:07    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         SPRAGUE-DAWLEY RATS FEMALE                   0 NG/KG      3 NG/KG      10 NG/KG     22 NG/KG     46 NG/KG     100          
                                                                                                                       NG/KG        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Hepatodiaphragmatic Nodule                                    2                         1            2                        
      Hyperplasia, Nodular                                                                    3            7           36           
      Inflammation                                    33 [1.1]     46 [1.2]     47 [1.1]     50 [1.4]     52 [1.2]     49 [1.3]     
      Mitotic Alteration                                                                      1 [2.0]      1 [2.0]                  
      Mixed Cell Focus                                 4            8            8                         2            4           
      Mixed Cell Focus, Multiple                      26           11           21           23           28           17           
      Necrosis                                         1 [2.0]      4 [2.3]      4 [2.0]      8 [2.3]     10 [1.9]     17 [2.5]     
      Pigmentation                                     4 [1.0]      9 [1.2]     34 [1.4]     48 [1.7]     52 [2.0]     53 [2.2]     
      Thrombosis                                                                                                        1 [3.0]     
      Toxic Hepatopathy                                             2 [1.0]      8 [1.3]     30 [1.2]     45 [1.8]     53 [3.5]     
      Artery, Inflammation, Chronic Active                                                                              2 [2.0]     
      Bile Duct, Cyst                                  3 [3.3]      1 [3.0]      2 [2.0]      2 [1.5]                  21 [2.9]     
      Bile Duct, Fibrosis                                           2 [2.0]                   1 [2.0]      3 [1.3]      4 [1.8]     
      Bile Duct, Hyperplasia                           5 [1.6]      4 [1.5]      7 [1.1]     22 [1.3]     40 [1.4]     53 [2.1]     
      Centrilobular, Degeneration                      2 [2.5]      2 [2.0]                   4 [2.3]      3 [2.0]      5 [2.0]     
      Hepatocyte, Hypertrophy                                      19 [1.2]     19 [1.2]     42 [1.5]     41 [2.0]     52 [3.2]     
      Hepatocyte, Multinucleated                                                16 [1.2]     26 [1.2]     36 [1.4]     51 [1.8]     
      Hepatocyte, Centrilobular, Atrophy                                                                   1 [2.0]                  
      Oval Cell, Hyperplasia                                        4 [1.0]      3 [1.3]     20 [1.3]     38 [1.5]     53 [2.3]     
      Portal, Fibrosis                                                                                     5 [1.8]     27 [2.0]     
   Mesentery                                          (2)          (2)                       (1)          (6)          (8)          
      Metaplasia, Osseous                              1 [2.0]                                                                      
      Artery, Inflammation, Chronic Active                          1 [3.0]                                4 [2.3]      7 [2.7]     
      Fat, Necrosis                                                 1 [3.0]                   1 [3.0]      1 [3.0]      1 [3.0]     
      Vein, Thrombosis                                 1 [3.0]                                                                      
   Oral Mucosa                                        (2)          (9)          (16)         (16)         (22)         (29)         
      Gingival, Hyperplasia, Squamous                  1 [4.0]      7 [1.4]     14 [1.6]     13 [1.6]     15 [2.2]     16 [2.3]     
   Pancreas                                           (51)         (54)         (52)         (53)         (52)         (51)         
      Hemorrhage                                                                                                        1 [3.0]     
      Inflammation, Acute                                                                     1 [4.0]                               
      Inflammation, Chronic Active                                               2 [1.5]      2 [1.0]      3 [1.3]      6 [2.0]     
      Necrosis                                                                                1 [3.0]                   1 [2.0]     
      Acinus, Atrophy                                  1 [1.0]      2 [1.5]      4 [1.5]      4 [1.5]      4 [1.5]      9 [2.2]     
      Acinus, Hyperplasia                              2 [2.5]                                1 [2.0]      2 [2.5]                  
      Acinus, Vacuolization Cytoplasmic                1 [2.0]                                1 [1.0]     15 [1.1]     42 [1.8]     
      Artery, Inflammation, Chronic Active                          1 [3.0]      1 [2.0]      2 [2.5]      2 [3.0]      7 [2.3]     
   Salivary Glands                                    (51)         (54)         (52)         (50)         (51)         (52)         
      Atrophy                                                                                 2 [2.5]      1 [2.0]                  
      Inflammation                                                               2 [2.0]      3 [2.3]                   1 [3.0]     
      Mineralization                                   1 [3.0]                                                                      
   Stomach, Forestomach                               (53)         (54)         (53)         (53)         (53)         (53)         
      Cyst, Squamous                                                             1 [2.0]                                            
      Edema                                                                                   1 [2.0]                   1 [1.0]     
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    3                                                              
                                                                                                                                   
NTP Experiment-Test: 96007-03         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 09/30/03    
Route: GAVAGE                                     TOXIC EQUIVALENCY FACTOR EVALUATION (TCDD)                      Time: 09:06:07    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         SPRAGUE-DAWLEY RATS FEMALE                   0 NG/KG      3 NG/KG      10 NG/KG     22 NG/KG     46 NG/KG     100          
                                                                                                                       NG/KG        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Erosion                                                                    1 [2.0]                   1 [2.0]                  
      Hyperkeratosis                                   1 [1.0]      1 [1.0]      1 [1.0]      1 [3.0]      2 [2.0]      3 [2.0]     
      Hyperplasia, Squamous                            3 [1.3]      4 [1.5]      4 [1.8]      2 [2.0]      7 [2.1]     11 [1.7]     
      Inflammation                                     1 [3.0]      1 [2.0]      2 [1.5]                   2 [1.5]      5 [1.8]     
      Mineralization                                                             1 [2.0]                                            
      Necrosis                                                                                                          1 [1.0]     
      Ulcer                                            2 [2.5]      1 [2.0]                   1 [1.0]      1 [2.0]      4 [2.5]     
   Stomach, Glandular                                 (53)         (54)         (53)         (53)         (53)         (53)         
      Diverticulum                                                               1                                                  
      Erosion                                          1 [3.0]                                                                      
      Metaplasia                                                                                           1 [2.0]                  
      Mineralization                                   3 [1.3]                                1 [2.0]      3 [1.7]                  
      Ulcer                                                                                                             2 [2.5]     
   Tooth                                              (16)         (16)         (12)         (13)         (14)         (18)         
      Peridontal Tissue, Fibrosis                      1 [2.0]                                                                      
      Peridontal Tissue, Inflammation                 15 [1.7]     16 [1.2]     12 [1.3]     13 [1.4]     14 [1.6]     18 [1.6]     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Blood Vessel                                       (53)         (54)         (53)         (53)         (53)         (53)         
      Thrombosis                                                                 1 [4.0]                                            
      Aorta, Mineralization                            1 [3.0]      1 [2.0]                                1 [2.0]                  
   Heart                                              (53)         (54)         (53)         (52)         (53)         (52)         
      Cardiomyopathy                                  10 [1.2]     12 [1.0]     22 [1.0]     25 [1.1]     32 [1.1]     36 [1.3]     
      Mineralization                                   1 [2.0]                                             1 [2.0]                  
      Artery, Inflammation                                                                                              1 [1.0]     
      Artery, Mineralization                                        1 [2.0]                                                         
      Artery, Thrombosis                                                                                                1 [2.0]     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (53)         (54)         (53)         (53)         (53)         (53)         
      Angiectasis                                     11 [1.5]     21 [1.9]     18 [1.6]     17 [1.8]     17 [1.6]     11 [1.7]     
      Atrophy                                          2 [2.5]                   4 [1.5]      5 [2.6]      5 [1.4]     27 [2.4]     
      Degeneration, Cystic                            11 [2.5]     15 [2.1]     21 [2.1]     18 [2.3]     17 [2.2]     17 [2.3]     
      Hyperplasia                                     16 [2.0]     16 [2.2]     18 [2.4]     25 [2.3]     29 [2.3]     30 [2.5]     
      Hypertrophy                                     41 [2.1]     43 [2.0]     46 [2.0]     40 [2.2]     45 [2.1]     47 [2.4]     
      Inflammation, Chronic Active                     1 [2.0]                                                                      
      Inflammation, Suppurative                        1 [1.0]                                                                      
      Mineralization                                                                                                    1 [2.0]     
      Necrosis                                                      1 [3.0]      2 [1.5]      1 [3.0]      3 [2.7]      1 [3.0]     
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    4                                                              
                                                                                                                                   
NTP Experiment-Test: 96007-03         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 09/30/03    
Route: GAVAGE                                     TOXIC EQUIVALENCY FACTOR EVALUATION (TCDD)                      Time: 09:06:07    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         SPRAGUE-DAWLEY RATS FEMALE                   0 NG/KG      3 NG/KG      10 NG/KG     22 NG/KG     46 NG/KG     100          
                                                                                                                       NG/KG        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Thrombosis                                                                              1 [2.0]                               
      Vacuolization Cytoplasmic                       11 [1.4]      7 [1.3]     12 [1.3]     21 [1.6]     18 [1.7]     15 [2.1]     
   Adrenal Medulla                                    (53)         (54)         (53)         (53)         (53)         (53)         
      Angiectasis                                                   1 [2.0]      2 [2.0]      1 [2.0]                               
      Hyperplasia                                     19 [1.8]     10 [2.0]     18 [2.0]      7 [1.6]     10 [2.4]      9 [1.9]     
      Inflammation, Suppurative                                                               1 [2.0]                               
   Islets, Pancreatic                                 (51)         (54)         (53)         (53)         (52)         (52)         
      Hyperplasia                                                                1 [4.0]      1 [4.0]                               
   Parathyroid Gland                                  (46)         (47)         (47)         (44)         (45)         (45)         
      Fibrosis                                                                   1 [3.0]                                            
      Hyperplasia                                      1 [2.0]                                                                      
   Pituitary Gland                                    (53)         (54)         (52)         (53)         (53)         (52)         
      Angiectasis                                     25 [2.3]     18 [2.6]     25 [2.3]     20 [2.1]     21 [1.9]      9 [2.1]     
      Atypia Cellular                                  1 [2.0]                                                                      
      Cyst                                             1 [2.0]      1 [3.0]                                             1 [2.0]     
      Cytoplasmic Alteration                           1 [1.0]                   1 [1.0]      4 [1.5]      3 [2.0]                  
      Developmental Malformation                       1                                                                            
      Inflammation, Chronic                                                                                             1 [2.0]     
      Vacuolization Cytoplasmic                                     3 [1.7]      1 [2.0]      2 [1.5]      2 [2.5]                  
      Pars Distalis, Hyperplasia                      19 [2.1]     19 [2.1]     16 [2.3]     21 [2.1]     26 [2.4]     19 [1.7]     
      Pars Intermedia, Hyperplasia                     2 [2.5]                                             1 [2.0]      1 [3.0]     
   Thyroid Gland                                      (52)         (54)         (53)         (51)         (53)         (52)         
      Angiectasis                                                   1 [2.0]      1 [1.0]      1 [2.0]      4 [2.0]      1 [1.0]     
      Cyst                                             1 [3.0]                                1 [2.0]                   1 [2.0]     
      Inflammation, Chronic Active                                               1 [2.0]                                            
      Inflammation, Suppurative                                                  1 [2.0]                                            
      C-Cell, Hyperplasia                             19 [1.8]     17 [2.2]     22 [2.1]     19 [2.3]     16 [1.9]     23 [1.9]     
      Follicular Cell, Hyperplasia                     2 [2.5]      2 [2.0]                                                         
      Follicular Cell, Hypertrophy                     3 [2.3]      4 [1.5]      4 [2.0]      7 [1.1]     10 [1.2]     17 [1.2]     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (50)         (52)         (53)         (52)         (51)         (53)         
      Hyperplasia, Basal Cell                          1 [2.0]                   1 [2.0]                                            
      Inflammation                                    41 [1.6]     40 [1.7]     35 [1.7]     34 [1.6]     28 [1.7]     26 [1.3]     
      Duct, Cyst                                      34 [2.2]     37 [2.1]     41 [2.2]     42 [2.0]     41 [2.2]     48 [2.3]     
   Ovary                                              (51)         (53)         (53)         (53)         (53)         (53)         
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    5                                                              
                                                                                                                                   
NTP Experiment-Test: 96007-03         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 09/30/03    
Route: GAVAGE                                     TOXIC EQUIVALENCY FACTOR EVALUATION (TCDD)                      Time: 09:06:07    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         SPRAGUE-DAWLEY RATS FEMALE                   0 NG/KG      3 NG/KG      10 NG/KG     22 NG/KG     46 NG/KG     100          
                                                                                                                       NG/KG        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
      Atrophy                                         49 [4.0]     46 [4.0]     50 [4.0]     44 [4.0]     50 [4.0]     31 [3.9]     
      Congestion                                                                              1 [2.0]                               
      Cyst                                            14 [2.5]     16 [1.9]     13 [2.4]     15 [2.2]     14 [2.2]     13 [2.5]     
      Fibrosis                                                                   1 [3.0]                   1 [2.0]                  
      Inflammation, Chronic Active                                                            1 [3.0]                   1 [3.0]     
      Inflammation, Suppurative                                                               1 [4.0]      1 [2.0]                  
      Artery, Inflammation, Chronic Active                                                                              1 [3.0]     
      Corpus Luteum, Cyst                                           1 [3.0]                                                         
      Periovarian Tissue, Inflammation, Suppurative                                           1 [2.0]                               
   Oviduct                                            (2)          (1)          (2)                       (1)          (1)          
      Inflammation                                     2 [3.0]      1 [3.0]      1 [2.0]                                1 [4.0]     
      Necrosis                                                                                             1 [4.0]                  
      Epithelium, Hyperplasia                                                    1 [2.0]                                            
   Uterus                                             (52)         (53)         (53)         (53)         (53)         (53)         
      Adenomyosis                                                                                          1 [2.0]                  
      Cyst                                                                                                              1 [3.0]     
      Hemorrhage                                       1 [2.0]                                                          1 [3.0]     
      Inflammation, Chronic Active                                  2 [3.0]      3 [2.7]                   3 [3.3]      1 [4.0]     
      Inflammation, Suppurative                        7 [1.9]      6 [1.8]     12 [2.4]      9 [2.1]     11 [2.3]      5 [2.2]     
      Metaplasia, Squamous                            29 [2.0]     31 [2.0]     28 [2.5]     23 [2.5]     32 [2.5]     17 [1.7]     
      Necrosis                                                                                1 [4.0]                               
      Ulcer                                                                      1 [2.0]                                            
      Cervix, Hyperplasia, Stromal                                  1 [4.0]      1 [4.0]      1 [4.0]      1 [4.0]                  
      Cervix, Inflammation, Suppurative                                                                    1 [3.0]                  
      Endometrium, Adenomyosis                                                   1 [3.0]                                            
      Endometrium, Hyperplasia, Cystic                30 [2.0]     33 [1.9]     35 [2.0]     27 [2.4]     31 [2.0]     19 [2.1]     
      Epithelium, Hyperplasia                                                                 1 [3.0]                               
      Serosa, Inflammation, Chronic Active                                       1 [3.0]                                            
   Vagina                                                          (1)          (1)          (3)          (3)          (1)          
      Cyst                                                                       1 [2.0]                   1 [2.0]                  
      Hyperplasia, Stromal                                          1 [3.0]                                                         
      Inflammation                                                                            2 [4.0]                               
      Necrosis                                                                                1 [4.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (53)         (54)         (53)         (53)         (53)         (53)         
      Atrophy                                                                                                           1 [4.0]     
      Hyperplasia                                     36 [3.0]     41 [3.2]     32 [3.2]     35 [3.1]     37 [2.9]     43 [2.8]     
   Lymph Node                                         (2)          (6)          (3)          (5)          (6)          (9)          
      Deep Cervical, Hemorrhage                                                               1 [3.0]                               
      Inguinal, Ectasia                                                                                    1 [2.0]                  
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    6                                                              
                                                                                                                                   
NTP Experiment-Test: 96007-03         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 09/30/03    
Route: GAVAGE                                     TOXIC EQUIVALENCY FACTOR EVALUATION (TCDD)                      Time: 09:06:07    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         SPRAGUE-DAWLEY RATS FEMALE                   0 NG/KG      3 NG/KG      10 NG/KG     22 NG/KG     46 NG/KG     100          
                                                                                                                       NG/KG        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Lumbar, Ectasia                                  1 [3.0]      2 [2.0]      1 [3.0]      2 [2.0]                               
      Lumbar, Hemorrhage                                                                      1 [2.0]                               
      Lumbar, Hyperplasia, Plasma Cell                              2 [3.0]                   1 [3.0]                               
      Lumbar, Pigmentation                                                                    1 [3.0]                               
      Mediastinal, Congestion                                                                              1 [2.0]                  
      Mediastinal, Ectasia                                                                                 1 [2.0]      3 [2.0]     
      Mediastinal, Hemorrhage                                       1 [3.0]                   1 [2.0]                   5 [2.2]     
      Mediastinal, Hyperplasia                                                                             1 [4.0]                  
      Mediastinal, Hyperplasia, Histiocytic                                      1 [2.0]                   1 [2.0]      1 [2.0]     
      Mediastinal, Hyperplasia, Lymphoid                            1 [2.0]                                                         
      Mediastinal, Hyperplasia, Plasma Cell                                                   1 [3.0]                               
      Mediastinal, Pigmentation                                                  1 [2.0]                                1 [2.0]     
      Renal, Ectasia                                                1 [3.0]                                                         
      Renal, Hyperplasia, Histiocytic                               1 [2.0]                                                         
   Lymph Node, Mandibular                             (51)         (54)         (52)         (50)         (51)         (52)         
      Congestion                                       1 [2.0]                                                                      
      Ectasia                                                                                              1 [2.0]      6 [2.7]     
      Hyperplasia, Lymphoid                                         3 [2.0]      3 [2.0]                                2 [2.0]     
      Hyperplasia, Plasma Cell                        25 [2.1]     31 [2.1]     23 [2.4]     22 [2.3]     15 [2.3]     16 [2.3]     
      Inflammation, Suppurative                                                                                         1 [2.0]     
   Lymph Node, Mesenteric                             (52)         (53)         (53)         (53)         (53)         (51)         
      Atrophy                                                       1 [3.0]                   1 [2.0]                               
      Ectasia                                                                                                           1 [2.0]     
      Hemorrhage                                                                                           1 [3.0]                  
      Hyperplasia, Histiocytic                         1 [2.0]                                             1 [3.0]      2 [2.5]     
      Hyperplasia, Plasma Cell                                                                             1 [3.0]                  
   Spleen                                             (51)         (54)         (53)         (53)         (52)         (52)         
      Hematopoietic Cell Proliferation                46 [1.5]     50 [1.6]     38 [1.3]     42 [1.6]     44 [1.5]     43 [1.5]     
      Hyperplasia, Lymphoid                            1 [2.0]                                                          4 [2.0]     
      Necrosis                                                                   1 [3.0]                                            
      Pigmentation                                    45 [1.5]     49 [1.4]     49 [1.5]     51 [1.5]     49 [1.6]     47 [1.4]     
      Lymphoid Follicle, Atrophy                       4 [2.3]                   1 [2.0]                   1 [2.0]      1 [2.0]     
   Thymus                                             (51)         (52)         (52)         (49)         (46)         (42)         
      Atrophy                                         36 [2.6]     41 [2.7]     44 [3.0]     41 [3.1]     44 [3.6]     42 [3.9]     
      Cyst                                                                                                 1 [3.0]      1 [2.0]     
      Hemorrhage                                       1 [3.0]                   1 [3.0]                                            
      Inflammation, Chronic Active                                                                         1 [3.0]                  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (53)         (54)         (53)         (53)         (53)         (53)         
      Cyst                                             4 [2.5]      3 [2.7]                   1 [3.0]      1 [2.0]      1 [2.0]     
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    7                                                              
                                                                                                                                   
NTP Experiment-Test: 96007-03         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 09/30/03    
Route: GAVAGE                                     TOXIC EQUIVALENCY FACTOR EVALUATION (TCDD)                      Time: 09:06:07    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         SPRAGUE-DAWLEY RATS FEMALE                   0 NG/KG      3 NG/KG      10 NG/KG     22 NG/KG     46 NG/KG     100          
                                                                                                                       NG/KG        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
INTEGUMENTARY SYSTEM - CONT                                                                                                         
      Hyperplasia                                     25 [1.4]     21 [1.4]     24 [1.5]     22 [1.4]     18 [1.2]     16 [1.5]     
      Inflammation, Chronic Active                                                                         1 [3.0]                  
      Inflammation, Granulomatous                      1 [2.0]      1 [2.0]      1 [2.0]                                1 [3.0]     
   Skin                                               (53)         (54)         (53)         (53)         (53)         (53)         
      Cyst Epithelial Inclusion                        1                                                                2           
      Hemorrhage                                                                 1 [3.0]                                            
      Hyperplasia, Squamous                                                      1 [2.0]                   1 [2.0]                  
      Inflammation, Chronic Active                                               2 [3.0]                                1 [3.0]     
      Necrosis                                                                   1 [3.0]                                            
      Ulcer                                                                      1 [3.0]                   1 [2.0]                  
      Epidermis, Inflammation                                                                                           1 [2.0]     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (53)         (54)         (53)         (53)         (53)         (53)         
      Fracture                                                                                                          1           
      Maxilla, Inflammation, Focal, Suppurative                     1 [2.0]                                                         
   Skeletal Muscle                                                              (1)          (2)                                    
      Hemorrhage                                                                              1 [3.0]                               
      Inflammation, Chronic Active                                                            1 [3.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (53)         (54)         (53)         (53)         (53)         (53)         
      Hemorrhage                                                                 1 [3.0]                                            
      Hydrocephalus                                                 1 [2.0]      1 [2.0]                                            
      Inflammation, Suppurative                                                                            1 [3.0]                  
      Mineralization                                                1 [2.0]      1 [2.0]                   2 [1.0]      2 [2.0]     
      Vacuolization Cytoplasmic, Focal                                           1 [1.0]                                            
      Artery, Thrombosis                                                                                   1 [3.0]                  
      Cerebellum, Developmental Malformation           1 [3.0]                                                                      
      Cerebellum, Necrosis                                                       1 [3.0]                                            
      Glial Cell, Hyperplasia                                       1 [2.0]                                             1 [2.0]     
   Spinal Cord                                                                  (1)                                                 
      Gliosis                                                                    1 [2.0]                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (53)         (54)         (53)         (52)         (53)         (52)         
      Congestion                                                                 2 [2.5]                                            
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    8                                                              
                                                                                                                                   
NTP Experiment-Test: 96007-03         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 09/30/03    
Route: GAVAGE                                     TOXIC EQUIVALENCY FACTOR EVALUATION (TCDD)                      Time: 09:06:07    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         SPRAGUE-DAWLEY RATS FEMALE                   0 NG/KG      3 NG/KG      10 NG/KG     22 NG/KG     46 NG/KG     100          
                                                                                                                       NG/KG        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
      Edema                                                                      2 [2.0]                   1 [2.0]                  
      Hemorrhage                                                    1 [2.0]                                             2 [2.5]     
      Infiltration Cellular, Histiocyte               41 [1.9]     46 [1.8]     43 [1.8]     43 [1.6]     49 [1.8]     50 [2.0]     
      Inflammation, Chronic Active                                                                                      1 [3.0]     
      Inflammation, Granulomatous                      2 [1.0]      1 [2.0]      2 [2.5]      2 [1.0]                               
      Inflammation, Suppurative                        1 [3.0]                                2 [1.5]                               
      Metaplasia, Squamous                             1 [1.0]                                             5 [2.2]      6 [2.2]     
      Mineralization                                   1 [2.0]                                             1 [1.0]      1 [2.0]     
      Necrosis                                                                                1 [2.0]                   1 [4.0]     
      Pigmentation                                                  1 [1.0]                                                         
      Alveolar Epithelium, Hyperplasia                12 [1.1]                                                                      
      Alveolar Epithelium, Metaplasia, Bronchiolar     2 [1.0]     19 [1.6]     33 [1.5]     35 [1.4]     45 [1.7]     46 [2.0]     
      Bronchiole, Dilatation                                                     1 [2.0]                                            
      Serosa, Inflammation, Focal, Suppurative                                                1 [2.0]                               
   Nose                                               (53)         (54)         (53)         (53)         (53)         (53)         
      Cyst, Squamous                                                                                       1 [3.0]                  
      Inflammation                                     2 [2.5]                                3 [1.7]      5 [2.0]      4 [2.5]     
      Goblet Cell, Septum, Hyperplasia                                                                     1 [2.0]                  
      Nasolacrimal Duct, Inflammation                  2 [2.0]                                                                      
      Nasolacrimal Duct, Respiratory Epithelium,                                                                                    
         Hyperplasia                                                                                       1 [2.0]                  
      Nasopharyngeal Duct, Inflammation                                                       1 [3.0]                   1 [4.0]     
      Nasopharyngeal Duct, Necrosis                                                           1 [3.0]                               
      Olfactory Epithelium, Degeneration                                                                   1 [2.0]                  
      Olfactory Epithelium, Inflammation                                                                   1 [3.0]      1 [2.0]     
      Respiratory Epithelium, Cyst                                                                         2 [2.0]                  
      Respiratory Epithelium, Hyperplasia                                                     1 [3.0]      2 [2.0]                  
      Septum, Hyperplasia, Squamous                                                                                     1 [2.0]     
      Septum, Inflammation                                                                                              2 [3.5]     
      Squamous Epithelium, Inflammation,                                                                                            
        Suppurative                                    1 [1.0]                                                                      
      Turbinate, Hyperplasia, Squamous                                                                                  1 [2.0]     
      Turbinate, Septum, Inflammation                                            1 [2.0]      1 [2.0]                   2 [2.5]     
      Turbinate, Respiratory Epithelium,                                                                                            
        Hyperplasia                                                              1 [2.0]      1 [3.0]                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (53)         (54)         (53)         (52)         (53)         (53)         
      Degeneration                                     1 [4.0]                                                                      
      Hemorrhage                                       1 [2.0]                                                                      
      Anterior Chamber, Inflammation, Suppurative                                                                       1 [4.0]     
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page    9                                                              
                                                                                                                                   
NTP Experiment-Test: 96007-03         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 09/30/03    
Route: GAVAGE                                     TOXIC EQUIVALENCY FACTOR EVALUATION (TCDD)                      Time: 09:06:07    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         SPRAGUE-DAWLEY RATS FEMALE                   0 NG/KG      3 NG/KG      10 NG/KG     22 NG/KG     46 NG/KG     100          
                                                                                                                       NG/KG        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
SPECIAL SENSES SYSTEM - CONT                                                                                                        
      Cornea, Inflammation, Suppurative                                          1 [1.0]                                1 [4.0]     
      Lens, Degeneration                                                                                   1 [4.0]                  
      Retina, Atrophy                                  5 [2.0]      5 [2.2]      5 [2.2]      3 [2.3]      4 [2.3]      6 [2.3]     
      Retina, Degeneration                                                                                 1 [3.0]                  
   Harderian Gland                                    (53)         (54)         (53)         (52)         (53)         (53)         
      Atrophy, Focal                                   1 [2.0]                                                                      
      Inflammation                                    12 [1.3]      3 [1.3]      2 [1.5]      2 [1.0]      8 [1.1]      6 [1.3]     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (53)         (54)         (53)         (53)         (53)         (53)         
      Calculus Gross Observation                                                                                        1 [4.0]     
      Calculus Micro Observation Only                  1 [2.0]      1 [0.0]      1 [0.0]      3 [0.0]      2 [2.0]                  
      Casts Protein                                    3 [1.3]      5 [1.4]      2 [1.0]                   1 [1.0]      1 [1.0]     
      Cyst                                             2 [2.5]                                             1 [2.0]      1 [2.0]     
      Fibrosis                                                      1 [2.0]                                                         
      Infarct                                                                    1 [3.0]                                            
      Inflammation, Chronic Active                     5 [1.2]      1 [1.0]                   1 [2.0]      1 [2.0]                  
      Inflammation, Suppurative                                                  2 [2.0]      1 [3.0]      1 [3.0]      2 [3.0]     
      Mineralization                                  40 [1.1]     39 [1.1]     30 [1.0]     32 [1.0]     42 [1.1]     42 [1.1]     
      Necrosis                                                                                1 [3.0]      1 [2.0]                  
      Nephropathy                                     34 [1.2]     26 [1.1]     32 [1.3]     36 [1.4]     39 [1.4]     52 [2.2]     
      Papilla, Necrosis                                                          1 [3.0]                                            
      Pelvis, Dilatation                               2 [3.0]      1 [2.0]      1 [3.0]                   2 [3.0]                  
      Pelvis, Inflammation                             2 [3.0]      1 [2.0]      1 [2.0]      1 [1.0]      4 [2.3]      2 [3.0]     
      Renal Tubule, Degeneration                                                                                        1 [2.0]     
      Transitional Epithelium, Hyperplasia             3 [2.3]      6 [1.7]      8 [1.8]      8 [1.3]     11 [2.0]     11 [1.8]     
   Ureter                                             (1)                                                                           
      Inflammation                                     1 [2.0]                                                                      
      Transitional Epithelium, Hyperplasia             1 [3.0]                                                                      
   Urinary Bladder                                    (52)         (53)         (53)         (52)         (53)         (53)         
      Calculus Micro Observation Only                               1                                                               
      Hemorrhage                                                    1 [3.0]                                                         
      Inflammation                                     6 [1.5]     10 [1.3]      4 [1.5]                   8 [2.0]      3 [1.7]     
      Metaplasia, Squamous                                                                                              1 [3.0]     
      Transitional Epithelium, Hyperplasia             1 [2.0]      2 [2.0]      1 [2.0]                   6 [2.2]      2 [2.5]     
                                                                                                                                    
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   10                                                              
                                                                                                                                   
NTP Experiment-Test: 96007-03         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 09/30/03    
Route: GAVAGE                                     TOXIC EQUIVALENCY FACTOR EVALUATION (TCDD)                      Time: 09:06:07    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         SPRAGUE-DAWLEY RATS FEMALE                   100 NG/                                                                       
                                                      KG/STOP                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
                                                                                                                                    
  Animals Initially In Study                          50                                                                            
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                16                                                                            
    Natural Death                                     13                                                                            
  Survivors                                                                                                                         
    Terminal Sacrifice                                21                                                                            
                                                                                                                                    
  Animals Examined Microscopically                    50                                                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Colon                             (49)                                                                          
      Parasite Metazoan                                1 [1.0]                                                                      
   Intestine Large, Rectum                            (50)                                                                          
      Parasite Metazoan                                5                                                                            
   Intestine Small, Jejunum                           (50)                                                                          
      Inflammation, Chronic                            1 [2.0]                                                                      
   Liver                                              (50)                                                                          
      Angiectasis                                      4 [1.5]                                                                      
      Atypia Cellular                                  1 [1.0]                                                                      
      Basophilic Focus                                 7                                                                            
      Basophilic Focus, Multiple                       9                                                                            
      Cholangiofibrosis                                1 [2.0]                                                                      
      Clear Cell Focus                                 6                                                                            
      Clear Cell Focus, Multiple                       2                                                                            
      Cytoplasmic Alteration                           1 [1.0]                                                                      
      Eosinophilic Focus                               6                                                                            
      Eosinophilic Focus, Multiple                    21                                                                            
      Fatty Change, Diffuse                           10 [1.4]                                                                      
      Fatty Change, Focal                              8 [1.3]                                                                      
      Hematopoietic Cell Proliferation                 2 [2.5]                                                                      
      Hepatodiaphragmatic Nodule                       1                                                                            
      Inflammation                                    43 [1.2]                                                                      
      Mixed Cell Focus                                 1                                                                            
      Mixed Cell Focus, Multiple                      28                                                                            
      Necrosis                                         8 [1.8]                                                                      
      Pigmentation                                    45 [1.8]                                                                      
      Toxic Hepatopathy                               16 [1.3]                                                                      
      Vacuolization Cytoplasmic                        1 [1.0]                                                                      
      Bile Duct, Cyst                                  6 [2.3]                                                                      
      Bile Duct, Fibrosis                              5 [1.2]                                                                      
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page   11                                                              
                                                                                                                                   
NTP Experiment-Test: 96007-03         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 09/30/03    
Route: GAVAGE                                     TOXIC EQUIVALENCY FACTOR EVALUATION (TCDD)                      Time: 09:06:07    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         SPRAGUE-DAWLEY RATS FEMALE                   100 NG/                                                                       
                                                      KG/STOP                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Bile Duct, Hyperplasia                           7 [1.3]                                                                      
      Hepatocyte, Hypertrophy                         22 [1.7]                                                                      
      Hepatocyte, Multinucleated                      32 [1.3]                                                                      
      Oval Cell, Hyperplasia                           1 [1.0]                                                                      
      Portal, Fibrosis                                 1 [2.0]                                                                      
      Serosa, Inflammation, Chronic Active             1 [3.0]                                                                      
   Mesentery                                          (1)                                                                           
      Artery, Inflammation, Chronic Active             1 [3.0]                                                                      
   Oral Mucosa                                        (11)                                                                          
      Gingival, Hyperplasia, Squamous                  8 [1.9]                                                                      
   Pancreas                                           (49)                                                                          
      Angiectasis                                      1 [2.0]                                                                      
      Basophilic Focus                                 1 [1.0]                                                                      
      Inflammation, Chronic Active                     4 [1.5]                                                                      
      Acinus, Atrophy                                  4 [1.8]                                                                      
      Artery, Inflammation, Chronic Active             2 [2.5]                                                                      
   Salivary Glands                                    (49)                                                                          
      Atrophy                                          2 [2.0]                                                                      
      Fibrosis                                         1 [2.0]                                                                      
      Inflammation                                     1 [1.0]                                                                      
   Stomach, Forestomach                               (50)                                                                          
      Hyperkeratosis                                   1 [2.0]                                                                      
      Hyperplasia, Squamous                            5 [1.8]                                                                      
      Inflammation                                     4 [2.0]                                                                      
      Ulcer                                            4 [2.3]                                                                      
   Stomach, Glandular                                 (50)                                                                          
      Erosion                                          1 [2.0]                                                                      
   Tongue                                             (1)                                                                           
      Inflammation, Chronic Active                     1 [3.0]                                                                      
   Tooth                                              (12)                                                                          
      Peridontal Tissue, Inflammation                 12 [1.6]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)                                                                          
      Cardiomyopathy                                  22 [1.4]                                                                      
      Inflammation                                     1 [2.0]                                                                      
      Atrium, Thrombosis                               2 [3.0]                                                                      
      Epicardium, Inflammation, Chronic Active         1 [2.0]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   12                                                              
                                                                                                                                   
NTP Experiment-Test: 96007-03         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 09/30/03    
Route: GAVAGE                                     TOXIC EQUIVALENCY FACTOR EVALUATION (TCDD)                      Time: 09:06:07    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         SPRAGUE-DAWLEY RATS FEMALE                   100 NG/                                                                       
                                                      KG/STOP                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)                                                                          
      Angiectasis                                     15 [1.9]                                                                      
      Atrophy                                          4 [1.8]                                                                      
      Degeneration, Cystic                            17 [2.2]                                                                      
      Hyperplasia                                     20 [2.6]                                                                      
      Hypertrophy                                     46 [2.1]                                                                      
      Necrosis                                         3 [3.0]                                                                      
      Vacuolization Cytoplasmic                       13 [1.3]                                                                      
   Adrenal Medulla                                    (50)                                                                          
      Hyperplasia                                     15 [2.1]                                                                      
   Islets, Pancreatic                                 (49)                                                                          
      Hyperplasia                                      1 [2.0]                                                                      
   Pituitary Gland                                    (50)                                                                          
      Angiectasis                                     15 [2.1]                                                                      
      Cytoplasmic Alteration                           1 [2.0]                                                                      
      Vacuolization Cytoplasmic                        3 [1.7]                                                                      
      Pars Distalis, Hyperplasia                      18 [1.8]                                                                      
   Thyroid Gland                                      (49)                                                                          
      Angiectasis                                      1 [2.0]                                                                      
      C-Cell, Hyperplasia                             15 [1.9]                                                                      
      Follicular Cell, Hypertrophy                     6 [1.5]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (49)                                                                          
      Atrophy                                          1 [2.0]                                                                      
      Hyperplasia, Basal Cell                          1 [1.0]                                                                      
      Hyperplasia, Squamous                            1 [3.0]                                                                      
      Inflammation                                    35 [1.5]                                                                      
      Duct, Cyst                                      35 [2.0]                                                                      
   Ovary                                              (49)                                                                          
      Atrophy                                         45 [4.0]                                                                      
      Cyst                                            16 [2.3]                                                                      
      Inflammation, Granulomatous                      1 [3.0]                                                                      
   Oviduct                                            (2)                                                                           
      Inflammation                                     2 [3.0]                                                                      
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page   13                                                              
                                                                                                                                   
NTP Experiment-Test: 96007-03         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 09/30/03    
Route: GAVAGE                                     TOXIC EQUIVALENCY FACTOR EVALUATION (TCDD)                      Time: 09:06:07    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         SPRAGUE-DAWLEY RATS FEMALE                   100 NG/                                                                       
                                                      KG/STOP                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
   Uterus                                             (50)                                                                          
      Inflammation, Chronic Active                     1 [3.0]                                                                      
      Inflammation, Suppurative                        9 [2.7]                                                                      
      Metaplasia, Squamous                            33 [2.1]                                                                      
      Cervix, Inflammation, Chronic Active             1 [3.0]                                                                      
      Endometrium, Hyperplasia, Cystic                32 [2.1]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)                                                                          
      Atrophy                                          1 [2.0]                                                                      
      Hyperplasia                                     36 [2.9]                                                                      
      Myelofibrosis                                    1 [2.0]                                                                      
   Lymph Node                                         (5)                                                                           
      Lumbar, Ectasia                                  2 [2.5]                                                                      
      Lumbar, Hyperplasia, Plasma Cell                 2 [2.5]                                                                      
      Mediastinal, Hemorrhage                          1 [2.0]                                                                      
      Mediastinal, Hyperplasia, Plasma Cell            1 [2.0]                                                                      
   Lymph Node, Mandibular                             (49)                                                                          
      Ectasia                                          2 [2.0]                                                                      
      Hyperplasia, Lymphoid                            2 [2.5]                                                                      
      Hyperplasia, Plasma Cell                        30 [2.2]                                                                      
   Lymph Node, Mesenteric                             (49)                                                                          
      Hyperplasia, Histiocytic                         1 [3.0]                                                                      
   Spleen                                             (49)                                                                          
      Hematopoietic Cell Proliferation                42 [1.5]                                                                      
      Hyperplasia, Lymphoid                            1 [2.0]                                                                      
      Pigmentation                                    42 [1.6]                                                                      
      Lymphoid Follicle, Atrophy                       1 [2.0]                                                                      
      Red Pulp, Atrophy                                1 [2.0]                                                                      
   Thymus                                             (49)                                                                          
      Atrophy                                         45 [3.3]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (50)                                                                          
      Cyst                                             4 [2.3]                                                                      
      Hyperplasia                                     19 [1.2]                                                                      
   Skin                                               (50)                                                                          
      Ulcer                                            1 [3.0]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page   14                                                              
                                                                                                                                   
NTP Experiment-Test: 96007-03         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 09/30/03    
Route: GAVAGE                                     TOXIC EQUIVALENCY FACTOR EVALUATION (TCDD)                      Time: 09:06:07    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         SPRAGUE-DAWLEY RATS FEMALE                   100 NG/                                                                       
                                                      KG/STOP                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)                                                                          
      Hemorrhage                                       1 [3.0]                                                                      
      Inflammation, Suppurative                        1 [2.0]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)                                                                          
      Infiltration Cellular, Histiocyte               41 [2.0]                                                                      
      Inflammation, Suppurative                        1 [3.0]                                                                      
      Metaplasia, Squamous                             3 [1.3]                                                                      
      Alveolar Epithelium, Metaplasia, Bronchiolar    31 [1.3]                                                                      
      Serosa, Inflammation, Suppurative                1 [3.0]                                                                      
   Nose                                               (50)                                                                          
      Inflammation                                     1 [1.0]                                                                      
      Goblet Cell, Respiratory Epithelium,                                                                                          
        Hyperplasia                                    1 [3.0]                                                                      
      Nasolacrimal Duct, Inflammation                  1 [3.0]                                                                      
      Olfactory Epithelium, Degeneration               1 [3.0]                                                                      
      Olfactory Epithelium, Inflammation               1 [3.0]                                                                      
      Olfactory Epithelium, Glands, Hyperplasia        1 [2.0]                                                                      
      Respiratory Epithelium, Cyst                     1 [2.0]                                                                      
      Respiratory Epithelium, Inflammation,                                                                                         
        Suppurative                                    1 [4.0]                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (50)                                                                          
      Retinal Detachment                               1 [3.0]                                                                      
      Bilateral, Cataract                              1 [3.0]                                                                      
      Retina, Atrophy                                  6 [1.8]                                                                      
      Retina, Degeneration                             1 [3.0]                                                                      
   Harderian Gland                                    (50)                                                                          
      Hemorrhage                                       1 [2.0]                                                                      
      Inflammation                                     9 [1.1]                                                                      
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                             Page   15                                                              
                                                                                                                                   
NTP Experiment-Test: 96007-03         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT18  
Study Type: CHRONIC                                  WITH AVERAGE SEVERITY GRADES[b]                              Date: 09/30/03    
Route: GAVAGE                                     TOXIC EQUIVALENCY FACTOR EVALUATION (TCDD)                      Time: 09:06:07    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         SPRAGUE-DAWLEY RATS FEMALE                   100 NG/                                                                       
                                                      KG/STOP                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)                                                                          
      Accumulation, Hyaline Droplet                    2 [2.5]                                                                      
      Casts Protein                                    1 [1.0]                                                                      
      Mineralization                                  42 [1.0]                                                                      
      Nephropathy                                     41 [1.4]                                                                      
      Papilla, Transitional Epithelium, Hyperplasia    1 [1.0]                                                                      
      Pelvis, Dilatation                               1 [2.0]                                                                      
      Transitional Epithelium, Hyperplasia             5 [1.4]                                                                      
   Urinary Bladder                                    (50)                                                                          
      Inflammation                                     2 [1.0]                                                                      
                                                                                                                                    
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Average severity grade (1-minimal;2-mild;3-moderate;4-marked)                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   16                                                              
                                                                                                                                   
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                             ----------              END OF REPORT             ----------                                           
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NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.