National Toxicology Program

National Toxicology Program
https://ntp.niehs.nih.gov/go/2641

TR 341 Rat Pathology Tables


                                     INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)
                                                           NITROFURANTOIN


NTP Experiment-Test: 05051-01                                                                                     Report: PEIRPT03
Study Type: CHRONIC                                                                                               Date: 09/07/94
Route: DOSED FEED                                                                                                 Time: 06:59:56




       Facility:  Southern Research Institute

       Chemical CAS #:  67-20-9

       Lock Date:  None

       Cage Range:  All

       Reasons For Removal:    All

       Removal Date Range:     All

       Treatment Groups:       Include All
































a  Number of animals examined microscopically at site and number of animals with lesion

                                                             Page   1

NTP Experiment-Test: 05051-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           NITROFURANTOIN                                      Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 06:59:56  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   UNTREATD     0.06%        0.13%                                                  
                                                    CONTROL                                                                         
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          50           50           50                                                  
  Early Deaths                                                                                                                      
    Moribund                                          22           12           17                                                  
    Dead                                               3           12            2                                                  
  Survivors                                                                                                                         
    Terminal Sacrifice                                25           26           31                                                  
  Animals Examined Microscopically                    50           50           50                                                  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Cecum                             (50)         (48)         (48)                                                
      Parasite Metazoan                                             1 (2%)       1 (2%)                                             
      Submucosa, Edema, Diffuse                        1 (2%)                                                                       
      Submucosa, Hemorrhage, Multifocal                1 (2%)                                                                       
      Submucosa, Inflammation, Diffuse                 1 (2%)                                                                       
   Intestine Large, Colon                             (50)         (46)         (48)                                                
      Parasite Metazoan                                6 (12%)      3 (7%)       2 (4%)                                             
      Mucosa, Mineralization                                        1 (2%)                                                          
   Intestine Large, Rectum                            (50)         (47)         (47)                                                
      Parasite Metazoan                                                          1 (2%)                                             
   Liver                                              (50)         (50)         (50)                                                
      Angiectasis, Focal                               1 (2%)                                                                       
      Basophilic Focus, Multiple                      10 (20%)      8 (16%)     10 (20%)                                            
      Clear Cell Focus                                 1 (2%)                    1 (2%)                                             
      Cytologic Alterations, Focal                     1 (2%)                    1 (2%)                                             
      Developmental Malformation                       2 (4%)       4 (8%)       1 (2%)                                             
      Focal Cellular Change                                                      1 (2%)                                             
      Hematopoietic Cell Proliferation                                           1 (2%)                                             
      Hyperplasia, Focal                               1 (2%)                                                                       
      Infiltration Cellular, Multifocal, Lymphocyte    2 (4%)       1 (2%)                                                          
      Inflammation, Focal, Granulomatous               2 (4%)                    2 (4%)                                             
      Inflammation, Granulomatous, Multifocal          2 (4%)       5 (10%)      7 (14%)                                            
      Necrosis, Coagulative, Diffuse                                1 (2%)                                                          
      Necrosis, Coagulative, Focal                     2 (4%)                    2 (4%)                                             
      Vacuolization Cytoplasmic, Diffuse                            5 (10%)      2 (4%)                                             
      Vacuolization Cytoplasmic, Focal                 3 (6%)       1 (2%)       1 (2%)                                             
      Vacuolization Cytoplasmic, Multifocal            2 (4%)       2 (4%)       1 (2%)                                             
      Bile Duct, Hyperplasia                           1 (2%)       7 (14%)      4 (8%)                                             
      Centrilobular, Congestion                                     1 (2%)                                                          
      Kupffer Cell, Pigmentation, Bile                              1 (2%)                                                          
   Mesentery                                          (8)          (9)          (10)                                                
      Hemorrhage, Focal                                                          1 (10%)                                            
      Infiltration Cellular, Lymphocyte                             1 (11%)                                                         
      Inflammation, Focal, Granulomatous                            1 (11%)                                                         
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    2                                                              
NTP Experiment-Test: 05051-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           NITROFURANTOIN                                      Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 06:59:56  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   UNTREATD     0.06%        0.13%                                                  
                                                    CONTROL                                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Fat, Fibrosis, Focal                                                       1 (10%)                                            
      Fat, Necrosis, Focal                             6 (75%)      7 (78%)      8 (80%)                                            
   Pancreas                                           (50)         (48)         (49)                                                
      Acinus, Atrophy                                                            1 (2%)                                             
      Acinus, Atrophy, Focal                           5 (10%)      5 (10%)      8 (16%)                                            
      Acinus, Atrophy, Multifocal                      1 (2%)                                                                       
      Acinus, Hyperplasia, Focal                                    2 (4%)       1 (2%)                                             
      Duct, Cyst                                       1 (2%)                                                                       
   Pharynx                                                                      (1)                                                 
      Hyperplasia                                                                1 (100%)                                           
      Inflammation, Suppurative                                                  1 (100%)                                           
   Stomach, Forestomach                               (50)         (48)         (50)                                                
      Cyst                                                          1 (2%)                                                          
      Edema                                            3 (6%)       3 (6%)       2 (4%)                                             
      Hyperkeratosis                                                2 (4%)       1 (2%)                                             
      Hyperplasia                                                   2 (4%)                                                          
      Inflammation, Chronic                                         1 (2%)       1 (2%)                                             
      Mineralization                                                1 (2%)                                                          
      Ulcer, Focal                                     3 (6%)       3 (6%)       1 (2%)                                             
      Epithelium, Hyperplasia                                                    1 (2%)                                             
   Stomach, Glandular                                 (50)         (48)         (50)                                                
      Dysplasia, Focal                                                           1 (2%)                                             
      Erosion                                          1 (2%)                    2 (4%)                                             
      Inflammation, Chronic                            1 (2%)       1 (2%)                                                          
      Mineralization                                                2 (4%)       3 (6%)                                             
      Necrosis, Focal                                                            1 (2%)                                             
      Ulcer                                                         1 (2%)                                                          
   Tongue                                                          (1)                                                              
      Inflammation                                                  1 (100%)                                                        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)                                                
      Fibrosis, Multifocal                            33 (66%)     34 (68%)     25 (50%)                                            
      Inflammation, Multifocal                         1 (2%)       1 (2%)       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Gland, Cortex                              (50)         (49)         (50)                                                
      Angiectasis                                      6 (12%)      5 (10%)      1 (2%)                                             
      Congestion                                       1 (2%)                                                                       
      Cyst                                             1 (2%)                                                                       
      Degeneration, Fatty, Focal                       2 (4%)       5 (10%)      7 (14%)                                            
      Hemorrhage, Diffuse                                           1 (2%)                                                          
      Hemorrhage, Focal                                             1 (2%)                                                          
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    3                                                              
NTP Experiment-Test: 05051-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           NITROFURANTOIN                                      Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 06:59:56  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   UNTREATD     0.06%        0.13%                                                  
                                                    CONTROL                                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Hyperplasia, Focal                               3 (6%)       3 (6%)       6 (12%)                                            
      Hypertrophy, Focal                                                         1 (2%)                                             
      Necrosis                                                      2 (4%)                                                          
      Vacuolization Cytoplasmic, Diffuse               1 (2%)                                                                       
      Vacuolization Cytoplasmic, Focal                 4 (8%)                    2 (4%)                                             
      Extra Adrenal Tissue, Accessory Adrenal                                                                                       
          Cortical Nodule                              1 (2%)                                                                       
   Adrenal Gland, Medulla                             (48)         (48)         (50)                                                
      Angiectasis                                      1 (2%)       1 (2%)       1 (2%)                                             
      Cyst, Multiple                                   1 (2%)                                                                       
      Hyperplasia, Focal                                            2 (4%)       1 (2%)                                             
      Infiltration Cellular, Multifocal, Lymphocyte                 1 (2%)                                                          
   Parathyroid Gland                                  (49)         (50)         (47)                                                
      Hyperplasia                                                                1 (2%)                                             
   Pituitary Gland                                    (50)         (48)         (48)                                                
      Pars Distalis, Angiectasis                      26 (52%)     24 (50%)     26 (54%)                                            
      Pars Distalis, Cyst                              8 (16%)      8 (17%)      4 (8%)                                             
      Pars Distalis, Cyst, Multiple                    5 (10%)      1 (2%)       3 (6%)                                             
      Pars Distalis, Hemorrhage                        1 (2%)       1 (2%)                                                          
      Pars Distalis, Hyperplasia, Focal                2 (4%)       7 (15%)      5 (10%)                                            
      Pars Distalis, Necrosis                          1 (2%)                                                                       
      Pars Distalis, Pigmentation                      1 (2%)                                                                       
   Thyroid Gland                                      (50)         (50)         (50)                                                
      Ultimobranchial Cyst                             1 (2%)       3 (6%)                                                          
      C-Cell, Hyperplasia, Focal                       5 (10%)      9 (18%)      4 (8%)                                             
      C-Cell, Hyperplasia, Multifocal                  3 (6%)       5 (10%)      2 (4%)                                             
      Follicle, Cyst                                   1 (2%)                                                                       
      Follicle, Hyperplasia, Cystic                                              1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   Tissue NOS                                                      (3)          (1)                                                 
      Hemorrhage                                                    1 (33%)                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (44)         (38)         (42)                                                
      Inflammation, Suppurative                        2 (5%)       5 (13%)      1 (2%)                                             
      Duct, Cyst                                      12 (27%)     13 (34%)      7 (17%)                                            
   Ovary                                              (50)         (50)         (50)                                                
      Cyst                                             2 (4%)       1 (2%)                                                          
   Uterus                                             (50)         (50)         (50)                                                
      Hemorrhage, Chronic, Focal                       1 (2%)                                                                       
      Hydrometra                                                    2 (4%)       2 (4%)                                             
      Cervix, Abscess                                               4 (8%)       2 (4%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    4                                                              
NTP Experiment-Test: 05051-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           NITROFURANTOIN                                      Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 06:59:56  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   UNTREATD     0.06%        0.13%                                                  
                                                    CONTROL                                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
      Cervix, Cyst                                     2 (4%)       5 (10%)      1 (2%)                                             
      Cervix, Cyst, Multiple                                        1 (2%)                                                          
      Cervix, Inflammation, Suppurative                1 (2%)       4 (8%)       3 (6%)                                             
      Endometrium, Cyst                                1 (2%)                                                                       
      Endometrium, Hyperplasia, Cystic                 5 (10%)     10 (20%)     10 (20%)                                            
      Endometrium, Inflammation, Suppurative                        2 (4%)       1 (2%)                                             
      Endometrium, Necrosis, Focal                                  1 (2%)                                                          
      Lumen, Inflammation, Suppurative                              1 (2%)                                                          
      Muscularis, Cyst                                                           1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Blood                                              (9)          (2)          (8)                                                 
      Anemia                                           1 (11%)                                                                      
      Anisocytosis                                                               1 (13%)                                            
   Bone Marrow                                        (49)         (48)         (50)                                                
      Hyperplasia, Reticulum Cell                      1 (2%)                    2 (4%)                                             
      Myelofibrosis                                                 2 (4%)       1 (2%)                                             
      Myeloid Cell, Hyperplasia                                     2 (4%)       4 (8%)                                             
   Lymph Node                                         (50)         (50)         (50)                                                
      Axillary, Hyperplasia, Lymphoid                               1 (2%)       1 (2%)                                             
      Axillary, Infiltration Cellular, Plasma Cell                               1 (2%)                                             
      Axillary, Infiltration Cellular, Histiocyte                                1 (2%)                                             
      Iliac, Hyperplasia, Lymphoid                                  1 (2%)                                                          
      Inguinal, Hyperplasia, Lymphoid                  1 (2%)                                                                       
      Mediastinal, Congestion                          1 (2%)       1 (2%)                                                          
      Mediastinal, Erythrophagocytosis                                           1 (2%)                                             
      Mediastinal, Hyperplasia, Lymphoid               1 (2%)                                                                       
      Renal, Sinus, Ectasia                                         1 (2%)                                                          
   Lymph Node, Mandibular                             (48)         (47)         (50)                                                
      Erythrophagocytosis                                                        1 (2%)                                             
      Hyperplasia, Lymphoid                            2 (4%)       1 (2%)       1 (2%)                                             
      Infiltration Cellular, Plasma Cell                                         2 (4%)                                             
      Inflammation, Suppurative                        1 (2%)                                                                       
   Lymph Node, Mesenteric                             (50)         (48)         (49)                                                
      Angiectasis                                      1 (2%)       1 (2%)                                                          
      Erythrophagocytosis                                                        1 (2%)                                             
      Hyperplasia, Lymphoid                            1 (2%)       2 (4%)                                                          
      Infiltration Cellular, Histiocyte                             1 (2%)       1 (2%)                                             
   Spleen                                             (50)         (49)         (50)                                                
      Atrophy                                                       1 (2%)                                                          
      Congestion                                       1 (2%)       4 (8%)       2 (4%)                                             
      Fibrosis                                                      1 (2%)                                                          
      Hematopoietic Cell Proliferation                 4 (8%)       6 (12%)      8 (16%)                                            
      Hemorrhage                                                                 1 (2%)                                             
      Hyperplasia, Focal, Lymphoid                                  2 (4%)                                                          
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    5                                                              
NTP Experiment-Test: 05051-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           NITROFURANTOIN                                      Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 06:59:56  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   UNTREATD     0.06%        0.13%                                                  
                                                    CONTROL                                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Necrosis, Coagulative                                                      1 (2%)                                             
      Pigmentation, Hemosiderin                        1 (2%)       1 (2%)       1 (2%)                                             
   Thymus                                             (43)         (34)         (40)                                                
      Congestion                                                    1 (3%)                                                          
      Hyperplasia, Lymphoid                                         1 (3%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (49)         (50)         (50)                                                
      Hyperplasia, Cystic                              5 (10%)     19 (38%)     11 (22%)                                            
      Hyperplasia, Lobular                             5 (10%)      5 (10%)      3 (6%)                                             
      Duct, Cyst                                      38 (78%)     33 (66%)     39 (78%)                                            
   Skin                                               (50)         (49)         (50)                                                
      Cyst Epithelial Inclusion                        1 (2%)       1 (2%)                                                          
      Hyperkeratosis, Focal                                         2 (4%)       1 (2%)                                             
      Hyperplasia, Focal                                            1 (2%)                                                          
      Subcutaneous Tissue, Cyst                                     1 (2%)                                                          
      Subcutaneous Tissue, Inflammation,                                                                                            
          Suppurative                                               2 (4%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)                                                
      Osteopetrosis                                    1 (2%)                                                                       
      Cranium, Hyperostosis                            4 (8%)       4 (8%)       5 (10%)                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)                                                
      Compression                                      6 (12%)      2 (4%)       1 (2%)                                             
      Degeneration, Multifocal                         1 (2%)       1 (2%)       3 (6%)                                             
      Hemorrhage, Focal                                             1 (2%)                                                          
      Hemorrhage, Multifocal                                        1 (2%)       1 (2%)                                             
      Hydrocephalus                                                 1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (50)         (50)                                                
      Angiectasis                                                                2 (4%)                                             
      Congestion                                       1 (2%)       4 (8%)       4 (8%)                                             
      Edema                                                         1 (2%)                                                          
      Infiltration Cellular, Focal, Histiocyte         2 (4%)       3 (6%)       5 (10%)                                            
      Infiltration Cellular, Multifocal, Lymphocyte                 2 (4%)                                                          
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    6                                                              
NTP Experiment-Test: 05051-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           NITROFURANTOIN                                      Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 06:59:56  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   UNTREATD     0.06%        0.13%                                                  
                                                    CONTROL                                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
      Inflammation, Chronic                            4 (8%)       2 (4%)       1 (2%)                                             
      Alveolar Epithelium, Hyperplasia, Focal                       1 (2%)       2 (4%)                                             
      Alveolar Epithelium, Hyperplasia, Multifocal                               1 (2%)                                             
      Bronchiole, Inflammation, Chronic Active                                   1 (2%)                                             
      Bronchiole, Inflammation, Suppurative                                      1 (2%)                                             
      Interstitium, Edema                                           2 (4%)                                                          
   Nose                                               (50)         (49)         (47)                                                
      Lumen, Foreign Body                              1 (2%)       1 (2%)       1 (2%)                                             
      Lumen, Fungus                                    2 (4%)                    1 (2%)                                             
      Lumen, Inflammation, Suppurative                 4 (8%)       1 (2%)       3 (6%)                                             
      Nasolacrimal Duct, Inflammation, Suppurative                  5 (10%)      4 (9%)                                             
   Trachea                                            (50)         (50)         (50)                                                
      Infiltration Cellular, Lymphocyte                1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Ear                                                (11)         (18)         (5)                                                 
      Middle Ear, Inflammation, Suppurative            1 (9%)                                                                       
   Eye                                                (1)          (19)         (6)                                                 
      Cataract                                                     16 (84%)      2 (33%)                                            
      Inflammation, Suppurative                        1 (100%)     1 (5%)                                                          
      Synechia                                                                   1 (17%)                                            
      Cornea, Edema                                                              2 (33%)                                            
      Lens, Mineralization                                          2 (11%)                                                         
      Retina, Degeneration                                         17 (89%)      3 (50%)                                            
   Harderian Gland                                    (1)          (9)                                                              
      Fibrosis                                         1 (100%)     8 (89%)                                                         
      Infiltration Cellular, Multifocal, Lymphocyte                 1 (11%)                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)                                                
      Mineralization, Multifocal                       1 (2%)       1 (2%)                                                          
      Nephropathy, Chronic                            44 (88%)     40 (80%)     48 (96%)                                            
      Pigmentation, Hemosiderin                                     1 (2%)                                                          
      Cortex, Fibrosis, Focal                                       1 (2%)                                                          
      Pelvis, Hydronephrosis                                        1 (2%)                                                          
      Pelvis, Infiltration Cellular, Lymphocyte        1 (2%)                                                                       
      Renal Tubule, Degeneration                       1 (2%)       2 (4%)                                                          
      Renal Tubule, Hyperplasia, Focal                              1 (2%)       1 (2%)                                             
      Renal Tubule, Pigmentation, Hemosiderin          1 (2%)       2 (4%)       2 (4%)                                             
   Urinary Bladder                                    (50)         (50)         (50)                                                
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    7                                                              
NTP Experiment-Test: 05051-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           NITROFURANTOIN                                      Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 06:59:56  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   UNTREATD     0.06%        0.13%                                                  
                                                    CONTROL                                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
URINARY SYSTEM - CONT                                                                                                               
      Mucosa, Hyperplasia, Diffuse                                               1 (2%)                                             
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    8                                                              
NTP Experiment-Test: 05051-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           NITROFURANTOIN                                      Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 06:59:56  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     UNTREATD     0.13%        0.25%                                                  
                                                    CONTROL                                                                         
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          50           50           50                                                  
  Early Deaths                                                                                                                      
    Moribund                                          23           22           21                                                  
    Dead                                               3            1            3                                                  
  Survivors                                                                                                                         
    Moribund                                           1                                                                            
    Terminal Sacrifice                                23           27           26                                                  
  Animals Examined Microscopically                    50           50           50                                                  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Cecum                             (50)         (50)         (48)                                                
      Parasite Metazoan                                1 (2%)                    2 (4%)                                             
      Submucosa, Edema                                 1 (2%)       1 (2%)       3 (6%)                                             
   Intestine Large, Colon                             (50)         (50)         (48)                                                
      Parasite Metazoan                                6 (12%)      5 (10%)      2 (4%)                                             
   Intestine Large, Rectum                            (50)         (48)         (47)                                                
      Parasite Metazoan                                             1 (2%)                                                          
   Liver                                              (50)         (50)         (50)                                                
      Angiectasis                                      2 (4%)       2 (4%)       1 (2%)                                             
      Basophilic Focus                                 1 (2%)                    1 (2%)                                             
      Congestion                                                    2 (4%)                                                          
      Cytologic Alterations, Focal                     5 (10%)      5 (10%)      4 (8%)                                             
      Cytologic Alterations, Multifocal                1 (2%)       2 (4%)       2 (4%)                                             
      Degeneration, Cystic, Focal                      4 (8%)       2 (4%)       2 (4%)                                             
      Developmental Malformation                                    1 (2%)       1 (2%)                                             
      Hematopoietic Cell Proliferation                              1 (2%)                                                          
      Hyperplasia, Nodular                             1 (2%)                    1 (2%)                                             
      Infiltration Cellular, Multifocal, Lymphocyte                              1 (2%)                                             
      Inflammation, Granulomatous, Multifocal                       3 (6%)       4 (8%)                                             
      Mixed Cell Focus                                                           1 (2%)                                             
      Necrosis, Coagulative, Multifocal                3 (6%)                    3 (6%)                                             
      Vacuolization Cytoplasmic, Diffuse               1 (2%)                    1 (2%)                                             
      Vacuolization Cytoplasmic, Focal                 3 (6%)       1 (2%)       1 (2%)                                             
      Vacuolization Cytoplasmic, Multifocal            2 (4%)                                                                       
      Bile Duct, Hyperplasia                          10 (20%)     15 (30%)     21 (42%)                                            
      Bile Duct, Hyperplasia, Multifocal               1 (2%)                                                                       
      Centrilobular, Degeneration                      1 (2%)                                                                       
      Portal, Fibrosis                                 1 (2%)       1 (2%)                                                          
      Serosa, Fibrosis, Focal                                                    1 (2%)                                             
   Mesentery                                          (6)          (9)          (6)                                                 
      Fibrosis, Focal                                                            1 (17%)                                            
      Inflammation, Granulomatous                      1 (17%)                                                                      
      Pigmentation, Hematoidin, Hemosiderin                                      1 (17%)                                            
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    9                                                              
NTP Experiment-Test: 05051-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           NITROFURANTOIN                                      Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 06:59:56  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     UNTREATD     0.13%        0.25%                                                  
                                                    CONTROL                                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Artery, Inflammation, Chronic                                 1 (11%)      1 (17%)                                            
      Artery, Mineralization                                                     1 (17%)                                            
      Artery, Thrombosis                                                         1 (17%)                                            
      Fat, Edema                                       1 (17%)                                                                      
      Fat, Necrosis, Focal                             1 (17%)      5 (56%)      3 (50%)                                            
      Vein, Mineralization                                          1 (11%)                                                         
   Pancreas                                           (50)         (50)         (49)                                                
      Hyperplasia, Focal                                                         1 (2%)                                             
      Pigmentation, Hematoidin, Hemosiderin                                      1 (2%)                                             
      Acinus, Atrophy                                  9 (18%)     10 (20%)     15 (31%)                                            
      Adventitia, Edema                                1 (2%)                    1 (2%)                                             
      Artery, Inflammation, Chronic                                 2 (4%)       1 (2%)                                             
   Salivary Glands                                    (48)         (50)         (50)                                                
      Hyperplasia                                                                1 (2%)                                             
   Stomach, Forestomach                               (49)         (50)         (49)                                                
      Edema                                            2 (4%)                    2 (4%)                                             
      Inflammation, Chronic                                         3 (6%)       1 (2%)                                             
      Inflammation, Suppurative                                                  1 (2%)                                             
      Mineralization                                                3 (6%)       3 (6%)                                             
      Necrosis                                         1 (2%)                                                                       
      Ulcer, Focal                                     1 (2%)                    2 (4%)                                             
   Stomach, Glandular                                 (49)         (50)         (50)                                                
      Edema                                                                      1 (2%)                                             
      Mineralization                                   1 (2%)       8 (16%)     14 (28%)                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Blood Vessel                                                    (1)                                                              
      Aorta, Mineralization                                         1 (100%)                                                        
   Heart                                              (50)         (50)         (50)                                                
      Fibrosis, Multifocal                            44 (88%)     45 (90%)     39 (78%)                                            
      Inflammation, Suppurative                                                  1 (2%)                                             
      Mineralization, Multifocal                                    1 (2%)                                                          
      Atrium, Thrombosis                               3 (6%)       3 (6%)       2 (4%)                                             
      Valve, Bacterium                                                           1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Gland, Cortex                              (50)         (50)         (50)                                                
      Angiectasis                                      1 (2%)       1 (2%)                                                          
      Cyst                                             1 (2%)                                                                       
      Fibrosis                                                                   1 (2%)                                             
      Hyperplasia, Focal                               3 (6%)       2 (4%)                                                          
      Hypertrophy, Focal                                            2 (4%)                                                          
      Necrosis, Multifocal                             1 (2%)                                                                       
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   10                                                              
NTP Experiment-Test: 05051-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           NITROFURANTOIN                                      Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 06:59:56  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     UNTREATD     0.13%        0.25%                                                  
                                                    CONTROL                                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Vacuolization Cytoplasmic, Diffuse                            1 (2%)                                                          
      Vacuolization Cytoplasmic, Focal                11 (22%)      6 (12%)     15 (30%)                                            
      Vacuolization Cytoplasmic, Multifocal                         1 (2%)       2 (4%)                                             
   Adrenal Gland, Medulla                             (50)         (50)         (50)                                                
      Angiectasis                                                                1 (2%)                                             
      Hemorrhage                                                    1 (2%)                                                          
      Hyperplasia, Focal                              10 (20%)      8 (16%)      7 (14%)                                            
      Hyperplasia, Multifocal                          1 (2%)       2 (4%)                                                          
      Mineralization                                   1 (2%)       1 (2%)                                                          
   Parathyroid Gland                                  (49)         (47)         (49)                                                
      Hyperplasia                                      3 (6%)      18 (38%)     23 (47%)                                            
   Pituitary Gland                                    (50)         (50)         (50)                                                
      Pars Distalis, Angiectasis                       9 (18%)      7 (14%)     14 (28%)                                            
      Pars Distalis, Cyst                              1 (2%)       2 (4%)       3 (6%)                                             
      Pars Distalis, Cyst, Multiple                                 1 (2%)       2 (4%)                                             
      Pars Distalis, Hemorrhage                                                  1 (2%)                                             
      Pars Distalis, Hyperplasia, Focal                7 (14%)      6 (12%)      5 (10%)                                            
      Pars Distalis, Hyperplasia, Multifocal                                     1 (2%)                                             
      Pars Distalis, Necrosis                                                    1 (2%)                                             
      Pars Nervosa, Infiltration Cellular                           1 (2%)                                                          
   Thyroid Gland                                      (50)         (50)         (50)                                                
      Ultimobranchial Cyst                                          1 (2%)       2 (4%)                                             
      C-Cell, Hyperplasia, Focal                       6 (12%)      2 (4%)       5 (10%)                                            
      C-Cell, Hyperplasia, Multifocal                  1 (2%)       1 (2%)                                                          
      Follicle, Cyst                                   1 (2%)       1 (2%)                                                          
      Follicle, Cyst, Multiple                         1 (2%)                                                                       
      Follicle, Hyperplasia, Cystic                    2 (4%)       1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Coagulating Gland                                  (1)          (1)                                                              
      Hyperplasia                                                   1 (100%)                                                        
      Inflammation, Chronic                            1 (100%)                                                                     
      Inflammation, Suppurative                                     1 (100%)                                                        
   Epididymis                                         (50)         (50)         (50)                                                
      Atypia Cellular                                                           12 (24%)                                            
      Degeneration                                                               1 (2%)                                             
      Depletion Cellular                              40 (80%)     43 (86%)     46 (92%)                                            
      Fibrosis                                                      1 (2%)                                                          
      Inflammation, Granulomatous                                   1 (2%)                                                          
   Preputial Gland                                    (48)         (50)         (47)                                                
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   11                                                              
NTP Experiment-Test: 05051-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           NITROFURANTOIN                                      Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 06:59:56  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     UNTREATD     0.13%        0.25%                                                  
                                                    CONTROL                                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
      Atrophy                                          1 (2%)                                                                       
      Fibrosis                                         7 (15%)      3 (6%)       5 (11%)                                            
      Hyperplasia                                      1 (2%)       1 (2%)                                                          
      Inflammation, Suppurative                       11 (23%)      6 (12%)                                                         
      Duct, Cyst                                       9 (19%)     13 (26%)      3 (6%)                                             
   Prostate                                           (50)         (50)         (49)                                                
      Cyst                                                          2 (4%)       2 (4%)                                             
      Cyst, Multiple                                                             3 (6%)                                             
      Fibrosis                                                      4 (8%)                                                          
      Inflammation                                                  1 (2%)                                                          
      Inflammation, Chronic                            3 (6%)       2 (4%)                                                          
      Inflammation, Chronic, Focal                     1 (2%)                                                                       
      Inflammation, Suppurative                       24 (48%)     19 (38%)     39 (80%)                                            
      Mineralization, Focal                            1 (2%)                                                                       
      Mineralization, Multifocal                                                 1 (2%)                                             
      Epithelium, Hyperplasia                                       1 (2%)       1 (2%)                                             
   Seminal Vesicle                                    (50)         (50)         (50)                                                
      Atrophy                                          1 (2%)       8 (16%)      8 (16%)                                            
      Dilatation                                                                 1 (2%)                                             
      Fibrosis                                                      1 (2%)                                                          
      Mineralization                                                1 (2%)                                                          
      Epithelium, Hyperplasia                                                    4 (8%)                                             
   Testes                                             (50)         (50)         (50)                                                
      Aspermatogenesis                                38 (76%)     40 (80%)     44 (88%)                                            
      Atrophy                                         41 (82%)     44 (88%)     48 (96%)                                            
      Degeneration                                                              36 (72%)                                            
      Hemorrhage                                       1 (2%)                                                                       
      Mineralization                                   1 (2%)                                                                       
      Arteriole, Necrosis, Fibrinoid                   1 (2%)       8 (16%)     15 (30%)                                            
      Interstitial Cell, Hyperplasia                   4 (8%)       3 (6%)       2 (4%)                                             
      Perivascular, Infiltration Cellular,                                                                                          
          Mononuclear Cell                             3 (6%)       9 (18%)     19 (38%)                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Blood                                              (18)         (13)         (10)                                                
      Anemia                                                        1 (8%)                                                          
      Hypochromasia                                    1 (6%)                                                                       
      Polychromasia                                    1 (6%)       1 (8%)       1 (10%)                                            
   Bone Marrow                                        (50)         (50)         (50)                                                
      Atrophy                                                                    1 (2%)                                             
      Hyperplasia, Reticulum Cell                      2 (4%)                                                                       
      Myelofibrosis                                    1 (2%)                    2 (4%)                                             
      Myeloid Cell, Hyperplasia                        1 (2%)       2 (4%)                                                          
   Lymph Node                                         (50)         (50)         (50)                                                
      Inguinal, Hyperplasia, Lymphoid                  1 (2%)       2 (4%)       1 (2%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   12                                                              
NTP Experiment-Test: 05051-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           NITROFURANTOIN                                      Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 06:59:56  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     UNTREATD     0.13%        0.25%                                                  
                                                    CONTROL                                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Mediastinal, Angiectasis                                                   2 (4%)                                             
      Mediastinal, Congestion                          1 (2%)       1 (2%)                                                          
      Mediastinal, Hyperplasia, Lymphoid                            1 (2%)       2 (4%)                                             
      Mediastinal, Pigmentation, Hemosiderin           1 (2%)                                                                       
      Pancreatic, Hyperplasia, Lymphoid                1 (2%)       1 (2%)       1 (2%)                                             
      Pancreatic, Inflammation, Granulomatous                                    1 (2%)                                             
      Pancreatic, Mineralization                                                 1 (2%)                                             
      Renal, Angiectasis                                                         4 (8%)                                             
      Renal, Hyperplasia, Lymphoid                                  1 (2%)       3 (6%)                                             
   Lymph Node, Mandibular                             (46)         (50)         (47)                                                
      Angiectasis                                                   1 (2%)       1 (2%)                                             
      Cyst                                             1 (2%)       1 (2%)       1 (2%)                                             
      Hyperplasia, Lymphoid                            4 (9%)       2 (4%)      10 (21%)                                            
      Infiltration Cellular, Plasma Cell                                         1 (2%)                                             
   Lymph Node, Mesenteric                             (49)         (48)         (49)                                                
      Angiectasis                                      3 (6%)                    3 (6%)                                             
      Ectasia                                                       2 (4%)                                                          
      Hyperplasia, Lymphoid                                         3 (6%)       4 (8%)                                             
      Inflammation, Chronic                            1 (2%)                                                                       
      Mineralization                                                             1 (2%)                                             
   Spleen                                             (50)         (50)         (50)                                                
      Congestion                                                    4 (8%)       4 (8%)                                             
      Fibrosis                                         1 (2%)                                                                       
      Fibrosis, Diffuse                                                          1 (2%)                                             
      Fibrosis, Focal                                  1 (2%)       2 (4%)       6 (12%)                                            
      Hematopoietic Cell Proliferation                 3 (6%)       1 (2%)       2 (4%)                                             
      Hyperplasia, Lymphoid                                                      2 (4%)                                             
      Necrosis                                         1 (2%)                                                                       
      Pigmentation, Hemosiderin                                                  1 (2%)                                             
   Thymus                                             (40)         (36)         (34)                                                
      Artery, Inflammation                                                       1 (3%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (46)         (49)         (46)                                                
      Duct, Cyst                                       6 (13%)     11 (22%)      7 (15%)                                            
   Skin                                               (50)         (50)         (50)                                                
      Alopecia                                         2 (4%)                                                                       
      Cyst Epithelial Inclusion                        2 (4%)       3 (6%)                                                          
      Fibrosis, Focal                                               3 (6%)       1 (2%)                                             
      Hyperkeratosis, Focal                            2 (4%)                    2 (4%)                                             
      Hyperplasia, Focal                                            1 (2%)       2 (4%)                                             
      Inflammation, Chronic                                                      2 (4%)                                             
      Ulcer, Focal                                                  1 (2%)       1 (2%)                                             
      Prepuce, Ulcer                                   1 (2%)                                                                       
      Subcutaneous Tissue, Mineralization, Focal                    1 (2%)                                                          
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   13                                                              
NTP Experiment-Test: 05051-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           NITROFURANTOIN                                      Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 06:59:56  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     UNTREATD     0.13%        0.25%                                                  
                                                    CONTROL                                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
INTEGUMENTARY SYSTEM - CONT                                                                                                         
      Subcutaneous Tissue, Necrosis, Focal                                       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)                                                
      Fibrous Osteodystrophy                                        5 (10%)      5 (10%)                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)                                                
      Compression                                      1 (2%)       2 (4%)       2 (4%)                                             
      Cerebellum, Degeneration                                      1 (2%)                                                          
      Cerebellum, Hemorrhage, Acute, Multifocal                                  1 (2%)                                             
      Cerebellum, Hemorrhage, Focal                    1 (2%)       1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (50)         (50)                                                
      Atelectasis                                      1 (2%)                    2 (4%)                                             
      Congestion                                       2 (4%)       2 (4%)       3 (6%)                                             
      Hemorrhage, Multifocal                           1 (2%)       1 (2%)                                                          
      Infiltration Cellular, Focal, Lymphocyte                                   1 (2%)                                             
      Infiltration Cellular, Histiocyte                3 (6%)       8 (16%)      2 (4%)                                             
      Inflammation, Suppurative                                     1 (2%)                                                          
      Alveolar Epithelium, Hyperplasia, Focal                       1 (2%)       3 (6%)                                             
      Alveolar Epithelium, Hyperplasia, Multifocal                  1 (2%)                                                          
      Alveolus, Edema                                               1 (2%)       1 (2%)                                             
      Alveolus, Mineralization, Multifocal                          1 (2%)                                                          
      Arteriole, Hypertrophy                           1 (2%)                                                                       
      Bronchiole, Foreign Body                                      1 (2%)                                                          
      Interstitium, Edema                                           1 (2%)                                                          
      Interstitium, Infiltration Cellular, Diffuse,                                                                                 
           Histiocyte                                  1 (2%)                                                                       
      Interstitium, Infiltration Cellular,                                                                                          
          Mononuclear Cell                                                       1 (2%)                                             
      Mediastinum, Pigmentation, Hemosiderin                        1 (2%)                                                          
   Nose                                               (50)         (49)         (48)                                                
      Lumen, Foreign Body                                           1 (2%)                                                          
      Lumen, Fungus                                    2 (4%)                                                                       
      Lumen, Inflammation, Suppurative                 3 (6%)       1 (2%)       1 (2%)                                             
      Nasolacrimal Duct, Inflammation, Suppurative     1 (2%)       4 (8%)       2 (4%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   14                                                              
NTP Experiment-Test: 05051-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                           NITROFURANTOIN                                      Date: 09/07/94  
Route: DOSED FEED                                                                                                 Time: 06:59:56  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     UNTREATD     0.13%        0.25%                                                  
                                                    CONTROL                                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (4)          (6)          (22)                                                
      Cataract                                         1 (25%)                  14 (64%)                                            
      Anterior Chamber, Hemorrhage                                               1 (5%)                                             
      Anterior Chamber, Inflammation, Suppurative                   1 (17%)      1 (5%)                                             
      Cornea, Infiltration Cellular, Lymphocyte                     1 (17%)                                                         
      Cornea, Inflammation, Focal, Granulomatous                                 1 (5%)                                             
      Cornea, Mineralization                                        1 (17%)                                                         
      Lens, Mineralization                                                       2 (9%)                                             
      Retina, Degeneration                             2 (50%)                  17 (77%)                                            
   Harderian Gland                                    (1)          (5)          (4)                                                 
      Atrophy                                                                    1 (25%)                                            
      Ectasia                                                       2 (40%)                                                         
      Fibrosis                                         1 (100%)     3 (60%)      4 (100%)                                           
   Lacrimal Gland                                     (1)                                                                           
      Atrophy                                          1 (100%)                                                                     
      Inflammation, Chronic                            1 (100%)                                                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)                                                
      Embolus Bacterial, Multifocal                                              1 (2%)                                             
      Infiltration Cellular, Multifocal, Lymphocyte                              1 (2%)                                             
      Inflammation, Chronic                                         1 (2%)                                                          
      Inflammation, Suppurative                                     1 (2%)       1 (2%)                                             
      Mineralization                                                2 (4%)       3 (6%)                                             
      Nephropathy, Chronic                            50 (100%)    48 (96%)     48 (96%)                                            
      Cortex, Cyst                                     2 (4%)       2 (4%)       2 (4%)                                             
      Cortex, Cyst, Multiple                                        3 (6%)       1 (2%)                                             
      Cortex, Necrosis                                 1 (2%)                                                                       
      Medulla, Congestion                                                        1 (2%)                                             
      Pelvis, Hydronephrosis                                        5 (10%)      2 (4%)                                             
      Pelvis, Transitional Epithelium, Hyperplasia                  5 (10%)      2 (4%)                                             
      Renal Tubule, Hyperplasia, Focal                 2 (4%)       2 (4%)       1 (2%)                                             
      Renal Tubule, Pigmentation, Hemosiderin          1 (2%)       1 (2%)                                                          
   Ureter                                                                       (1)                                                 
      Dilatation                                                                 1 (100%)                                           
   Urinary Bladder                                    (50)         (50)         (50)                                                
      Mucosa, Hyperplasia                                           1 (2%)       2 (4%)                                             
      Mucosa, Inflammation, Chronic                                 1 (2%)                                                          
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   15                                                              
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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.