Skip to Main Navigation
Skip to Page Content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it's official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Share This:
https://ntp.niehs.nih.gov/go/3458

TDMS Study 05040-01 Pathology Tables


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


NTP Experiment-Test: 05040-01                                                                                     Report: PEIRPT03
Study Type: CHRONIC                                                                                               Date: 09/05/94
Route: GAVAGE                                                                                                     Time: 10:19:30




       Facility:  American Biogenics Corp.

       Chemical CAS #:  000123319

       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: 05040-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:30  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          65           65           65                                                  
  Scheduled Sacrifice                                 10           10           10                                                  
  Early Deaths                                                                                                                      
    Moribund                                          14           19           14                                                  
    Dead                                               1            6            6                                                  
    Gavage Death                                                    3            3                                                  
  Survivors                                                                                                                         
    Terminal Sacrifice                                39           27           31                                                  
    Dead                                               1                                                                            
    Accident                                                                     1                                                  
  Animals Examined Microscopically                    55           55           55                                                  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Small, Duodenum                          (55)         (28)         (55)                                                
      Erosion                                                                    1 (2%)                                             
      Inflammation, Suppurative                                                  1 (2%)                                             
   Liver                                              (55)         (55)         (55)                                                
      Basophilic Focus                                30 (55%)     38 (69%)     30 (55%)                                            
      Clear Cell Focus                                 5 (9%)       6 (11%)      5 (9%)                                             
      Congestion                                       1 (2%)       1 (2%)       1 (2%)                                             
      Cytomegaly                                       1 (2%)       2 (4%)       2 (4%)                                             
      Degeneration, Cystic                             1 (2%)       1 (2%)                                                          
      Eosinophilic Focus                               1 (2%)       2 (4%)                                                          
      Fatty Change                                     9 (16%)     10 (18%)      9 (16%)                                            
      Fibrosis, Focal                                                            2 (4%)                                             
      Focal Cellular Change                                         1 (2%)       1 (2%)                                             
      Hematopoietic Cell Proliferation                 2 (4%)       2 (4%)       1 (2%)                                             
      Hemorrhage                                                    1 (2%)                                                          
      Hepatodiaphragmatic Nodule                       9 (16%)     10 (18%)     11 (20%)                                            
      Hyperplasia, Focal                                                         1 (2%)                                             
      Inflammation, Chronic                           39 (71%)     30 (55%)     31 (56%)                                            
      Inflammation, Granulomatous                      1 (2%)                    1 (2%)                                             
      Mineralization                                                3 (5%)       1 (2%)                                             
      Mixed Cell Focus                                 4 (7%)       1 (2%)       2 (4%)                                             
      Necrosis, Coagulative                            4 (7%)       3 (5%)       4 (7%)                                             
      Arteriole, Inflammation, Proliferative                                     1 (2%)                                             
      Bile Duct, Hyperplasia                          41 (75%)     36 (65%)     41 (75%)                                            
      Centrilobular, Atrophy                           4 (7%)       3 (5%)      10 (18%)                                            
      Sinusoid, Dilatation                             3 (5%)       1 (2%)       3 (5%)                                             
   Mesentery                                          (7)          (13)         (16)                                                
      Pigmentation, Hemosiderin                                                  1 (6%)                                             
      Arteriole, Degeneration, Hyaline                              1 (8%)                                                          
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    2                                                              
NTP Experiment-Test: 05040-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:30  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Arteriole, Inflammation, Chronic                 1 (14%)      1 (8%)                                                          
      Fat, Hemorrhage                                                            2 (13%)                                            
      Fat, Inflammation, Acute                                                   1 (6%)                                             
      Fat, Inflammation, Chronic                                    6 (46%)      5 (31%)                                            
      Fat, Inflammation, Granulomatous                              1 (8%)                                                          
      Fat, Mineralization                                           1 (8%)                                                          
      Fat, Necrosis                                    3 (43%)      5 (38%)      7 (44%)                                            
      Fat, Pigmentation, Hemosiderin                                             1 (6%)                                             
   Pancreas                                           (55)         (28)         (55)                                                
      Atrophy                                          2 (4%)       1 (4%)                                                          
      Focal Cellular Change                                                      1 (2%)                                             
      Inflammation, Chronic                            1 (2%)                                                                       
      Duct, Fibrosis                                   1 (2%)                                                                       
      Duct, Necrosis, Coagulative                                   1 (4%)                                                          
   Pharynx                                                         (1)                                                              
      Hyperkeratosis                                                1 (100%)                                                        
      Inflammation, Chronic                                         1 (100%)                                                        
   Salivary Glands                                    (55)         (26)         (55)                                                
      Atrophy, Focal                                   1 (2%)       1 (4%)       3 (5%)                                             
      Cytoplasmic Alteration                           3 (5%)                    2 (4%)                                             
      Arteriole, Inflammation, Proliferative                                     1 (2%)                                             
      Duct, Ectasia                                                 1 (4%)                                                          
      Duct, Inflammation, Chronic                     13 (24%)      1 (4%)       6 (11%)                                            
      Duct, Metaplasia, Squamous                       5 (9%)       3 (12%)     12 (22%)                                            
   Stomach, Forestomach                               (55)         (28)         (54)                                                
      Acanthosis                                       1 (2%)       2 (7%)       2 (4%)                                             
      Hyperkeratosis                                   1 (2%)       2 (7%)       2 (4%)                                             
      Hyperplasia, Papillary                           1 (2%)                                                                       
      Inflammation, Acute                                           1 (4%)                                                          
      Inflammation, Chronic                            1 (2%)                    1 (2%)                                             
      Ulcer                                            3 (5%)       2 (7%)                                                          
   Stomach, Glandular                                 (55)         (28)         (54)                                                
      Inflammation, Acute                                           1 (4%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (55)         (28)         (55)                                                
      Cardiomyopathy                                  46 (84%)     20 (71%)     42 (76%)                                            
      Atrium, Inflammation, Chronic                                              1 (2%)                                             
      Atrium, Thrombosis                                            1 (4%)       2 (4%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    3                                                              
NTP Experiment-Test: 05040-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:30  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Gland, Cortex                              (55)         (55)         (55)                                                
      Accessory Adrenal Cortical Nodule                1 (2%)                    2 (4%)                                             
      Angiectasis                                      5 (9%)       6 (11%)      4 (7%)                                             
      Atrophy                                                                    1 (2%)                                             
      Cyst                                                          1 (2%)       3 (5%)                                             
      Degeneration, Fatty, Focal                       8 (15%)      8 (15%)      8 (15%)                                            
      Degeneration, Focal                              1 (2%)                    1 (2%)                                             
      Hematopoietic Cell Proliferation                 2 (4%)       2 (4%)       2 (4%)                                             
      Hyperplasia                                     10 (18%)     11 (20%)     12 (22%)                                            
      Hypertrophy                                      1 (2%)       1 (2%)                                                          
      Hypertrophy, Focal                               1 (2%)                                                                       
      Necrosis, Coagulative                                         3 (5%)                                                          
      Pigmentation, Hemosiderin                        1 (2%)                                                                       
      Vacuolization Cytoplasmic                        3 (5%)       1 (2%)       7 (13%)                                            
      Capsule, Hyperplasia                                          3 (5%)       1 (2%)                                             
   Adrenal Gland, Medulla                             (54)         (55)         (54)                                                
      Hyperplasia                                     13 (24%)      8 (15%)     11 (20%)                                            
   Islets, Pancreatic                                 (53)         (28)         (55)                                                
      Hyperplasia                                      1 (2%)                                                                       
   Parathyroid Gland                                  (54)         (22)         (54)                                                
      Hyperplasia                                      3 (6%)       2 (9%)       2 (4%)                                             
   Pituitary Gland                                    (54)         (54)         (54)                                                
      Cyst                                                          1 (2%)                                                          
      Hyperplasia                                                                1 (2%)                                             
      Pars Distalis, Angiectasis                       1 (2%)       2 (4%)                                                          
      Pars Distalis, Cyst                             23 (43%)     18 (33%)     20 (37%)                                            
      Pars Distalis, Hemorrhage                        1 (2%)                                                                       
      Pars Distalis, Hyperplasia                      28 (52%)     22 (41%)     26 (48%)                                            
      Pars Intermedia, Cyst                            1 (2%)                                                                       
      Rathke's Cleft, Crystals                                                   1 (2%)                                             
   Thyroid Gland                                      (55)         (54)         (55)                                                
      Ultimobranchial Cyst                             1 (2%)       1 (2%)                                                          
      C-Cell, Hyperplasia                             19 (35%)     15 (28%)     14 (25%)                                            
      Follicle, Cyst                                                1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    4                                                              
NTP Experiment-Test: 05040-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:30  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (51)         (24)         (52)                                                
      Abscess                                          1 (2%)                                                                       
      Cyst                                             4 (8%)       1 (4%)       9 (17%)                                            
      Hyperplasia                                      2 (4%)       2 (8%)                                                          
      Inflammation, Chronic                            7 (14%)      2 (8%)       5 (10%)                                            
      Inflammation, Granulomatous                                   1 (4%)       1 (2%)                                             
      Inflammation, Suppurative                        5 (10%)      1 (4%)       2 (4%)                                             
      Pigmentation, Hemosiderin                                     1 (4%)                                                          
   Ovary                                              (55)         (29)         (55)                                                
      Atrophy                                          2 (4%)       1 (3%)                                                          
      Corpus Luteum, Cyst                                           1 (3%)       1 (2%)                                             
      Follicle, Cyst                                   2 (4%)       1 (3%)                                                          
      Periovarian Tissue, Cyst                         1 (2%)       1 (3%)       2 (4%)                                             
   Oviduct                                                                      (2)                                                 
      Inflammation, Chronic                                                      1 (50%)                                            
   Uterus                                             (55)         (55)         (55)                                                
      Inflammation, Suppurative                                     1 (2%)       2 (4%)                                             
      Cervix, Abscess                                  2 (4%)       6 (11%)      4 (7%)                                             
      Cervix, Inflammation, Proliferative                           1 (2%)       1 (2%)                                             
      Cervix, Prolapse                                 2 (4%)                                                                       
      Cervix, Epithelium, Degeneration, Mucoid                                   1 (2%)                                             
      Endometrium, Hyperplasia, Cystic                17 (31%)     16 (29%)     15 (27%)                                            
   Vagina                                             (2)          (1)          (1)                                                 
      Dilatation                                       1 (50%)                                                                      
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Blood                                              (8)          (10)         (18)                                                
      Neutrophilia                                                  2 (20%)      2 (11%)                                            
      Thrombocytopenia                                              1 (10%)                                                         
      Erythrocyte, Poikilocytosis                                   1 (10%)                                                         
   Bone Marrow                                        (55)         (28)         (55)                                                
      Myelofibrosis                                    1 (2%)       1 (4%)                                                          
      Erythroid Cell, Hyperplasia                      1 (2%)                    1 (2%)                                             
      Myeloid Cell, Hyperplasia                        1 (2%)                                                                       
   Lymph Node                                         (55)         (28)         (55)                                                
      Mediastinal, Hyperplasia, Macrophage                                       1 (2%)                                             
      Mediastinal, Hyperplasia, Plasma Cell                         1 (4%)                                                          
      Mediastinal, Pigmentation, Hemosiderin                                     1 (2%)                                             
      Mediastinal, Sinus, Ectasia                                   1 (4%)                                                          
      Pancreatic, Hematopoietic Cell Proliferation     1 (2%)                                                                       
      Pancreatic, Sinus, Ectasia                                    1 (4%)                                                          
   Lymph Node, Mandibular                             (55)         (26)         (52)                                                
      Hyperplasia, Lymphoid                                                      1 (2%)                                             
      Hyperplasia, Macrophage                                       1 (4%)                                                          
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    5                                                              
NTP Experiment-Test: 05040-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:30  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Hyperplasia, Plasma Cell                         4 (7%)       1 (4%)       2 (4%)                                             
      Sinus, Ectasia                                   3 (5%)                    2 (4%)                                             
   Lymph Node, Mesenteric                             (53)         (28)         (54)                                                
      Congestion                                       1 (2%)                    1 (2%)                                             
      Hemorrhage                                                    1 (4%)                                                          
      Hyperplasia, Macrophage                          2 (4%)                                                                       
      Hyperplasia, Plasma Cell                                                   1 (2%)                                             
      Sinus, Ectasia                                   6 (11%)      2 (7%)       3 (6%)                                             
   Spleen                                             (55)         (55)         (55)                                                
      Fibrosis                                                      1 (2%)       2 (4%)                                             
      Hematopoietic Cell Proliferation                 2 (4%)       5 (9%)       2 (4%)                                             
      Infarct                                                       1 (2%)       1 (2%)                                             
      Inflammation, Chronic                                         1 (2%)                                                          
      Pigmentation, Hemosiderin                        1 (2%)       2 (4%)                                                          
   Thymus                                             (52)         (27)         (51)                                                
      Cyst                                             4 (8%)       1 (4%)       5 (10%)                                            
      Arteriole, Mediastinum, Inflammation, Chronic    1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (55)         (55)         (54)                                                
      Abscess                                                                    1 (2%)                                             
      Cyst                                            16 (29%)     12 (22%)     14 (26%)                                            
      Hyperplasia                                     36 (65%)     45 (82%)     30 (56%)                                            
      Mineralization                                                1 (2%)                                                          
      Duct, Fibrosis                                   1 (2%)                                                                       
   Skin                                               (55)         (30)         (55)                                                
      Abscess                                                       1 (3%)                                                          
      Cyst Epithelial Inclusion                        1 (2%)       1 (3%)       1 (2%)                                             
      Inflammation, Chronic                                         2 (7%)                                                          
      Ulcer                                            2 (4%)       2 (7%)       2 (4%)                                             
      Subcutaneous Tissue, Cyst                                                  1 (2%)                                             
      Subcutaneous Tissue, Inflammation, Chronic       2 (4%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (55)         (28)         (55)                                                
      Compression                                      7 (13%)      6 (21%)      2 (4%)                                             
      Cerebrum, Mineralization                                                   1 (2%)                                             
      Meninges, Hemorrhage                             1 (2%)                                                                       
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    6                                                              
NTP Experiment-Test: 05040-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:30  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
NERVOUS SYSTEM - CONT                                                                                                               
      Pons, Hematocyst                                 1 (2%)                                                                       
      Ventricle, Dilatation                            2 (4%)                    1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (55)         (29)         (55)                                                
      Congestion                                                    2 (7%)                                                          
      Edema                                                                      1 (2%)                                             
      Hemorrhage                                       1 (2%)                                                                       
      Hyperplasia, Macrophage                          1 (2%)       1 (3%)       1 (2%)                                             
      Hyperplasia, Adenomatous                         1 (2%)       1 (3%)       2 (4%)                                             
      Pigmentation, Hemosiderin                        1 (2%)                                                                       
      Interstitium, Inflammation, Chronic              3 (5%)       2 (7%)       1 (2%)                                             
      Interstitium, Inflammation, Granulomatous                                  1 (2%)                                             
      Pleura, Inflammation, Chronic                    1 (2%)                    3 (5%)                                             
   Nose                                               (55)         (28)         (55)                                                
      Exudate                                                       1 (4%)                                                          
      Hemorrhage                                                                 1 (2%)                                             
      Inflammation, Chronic                            7 (13%)      4 (14%)      4 (7%)                                             
      Inflammation, Suppurative                        1 (2%)                                                                       
      Lumen, Foreign Body                              1 (2%)                                                                       
      Nasolacrimal Duct, Cyst                                                    1 (2%)                                             
      Nasolacrimal Duct, Inflammation, Chronic        39 (71%)     17 (61%)     28 (51%)                                            
      Nasolacrimal Duct, Inflammation, Suppurative     1 (2%)                                                                       
      Nasolacrimal Duct, Metaplasia, Squamous         52 (95%)     20 (71%)     40 (73%)                                            
   Trachea                                            (55)         (28)         (55)                                                
      Inflammation, Chronic                            3 (5%)       2 (7%)                                                          
      Glands, Cyst                                     1 (2%)       1 (4%)       6 (11%)                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Eye                                                (2)          (1)          (6)                                                 
      Hemorrhage                                                                 3 (50%)                                            
      Cornea, Proliferation                                                      1 (17%)                                            
      Retina, Atrophy                                  2 (100%)                  2 (33%)                                            
   Harderian Gland                                    (2)          (1)          (1)                                                 
      Inflammation, Chronic                            2 (100%)     1 (100%)                                                        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (55)         (55)         (55)                                                
      Cyst                                                          1 (2%)       1 (2%)                                             
      Inflammation, Chronic                           17 (31%)     14 (25%)     18 (33%)                                            
      Mineralization                                   3 (5%)       1 (2%)       4 (7%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    7                                                              
NTP Experiment-Test: 05040-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:30  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS FEMALE                   VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
URINARY SYSTEM - CONT                                                                                                               
      Necrosis, Coagulative                                                      1 (2%)                                             
      Nephropathy                                     47 (85%)     47 (85%)     46 (84%)                                            
      Pelvis, Dilatation                               1 (2%)       1 (2%)                                                          
      Renal Tubule, Inflammation, Suppurative          2 (4%)                                                                       
      Transitional Epithelium, Hyperplasia,                                                                                         
          Papillary                                                 1 (2%)                                                          
   Urinary Bladder                                    (55)         (27)         (51)                                                
      Inflammation, Chronic                            5 (9%)       4 (15%)      3 (6%)                                             
      Transitional Epithelium, Hyperplasia,                                                                                         
          Papillary                                                              1 (2%)                                             
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    8                                                              
NTP Experiment-Test: 05040-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:30  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially In Study                          65           65           65                                                  
  Scheduled Sacrifice                                 10           10           10                                                  
  Early Deaths                                                                                                                      
    Moribund                                          13           25           22                                                  
    Gavage Death                                       2            5            7                                                  
    Dead                                              13            7            8                                                  
  Survivors                                                                                                                         
    Terminal Sacrifice                                27           18           18                                                  
  Animals Examined Microscopically                    55           55           55                                                  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Cecum                             (50)         (34)         (50)                                                
      Ulcer                                                         1 (3%)                                                          
      Venule, Thrombosis                                            1 (3%)                                                          
   Intestine Large, Colon                             (51)         (35)         (53)                                                
      Mineralization                                                             1 (2%)                                             
      Muscularis, Inflammation, Chronic                                          1 (2%)                                             
      Muscularis, Mineralization                                                 2 (4%)                                             
      Serosa, Inflammation, Chronic                                 1 (3%)                                                          
   Intestine Large, Rectum                            (53)         (32)         (52)                                                
      Edema                                                         1 (3%)                                                          
      Hemorrhage                                                    1 (3%)                                                          
      Muscularis, Mineralization                                                 1 (2%)                                             
   Intestine Small                                    (52)         (36)         (55)                                                
      Capillary, Degeneration, Hyaline                                           1 (2%)                                             
   Intestine Small, Duodenum                          (52)         (35)         (55)                                                
      Muscularis, Inflammation, Chronic                                          1 (2%)                                             
   Intestine Small, Ileum                             (48)         (33)         (49)                                                
      Capillary, Degeneration, Hyaline                                           1 (2%)                                             
      Muscularis, Inflammation, Chronic                                          1 (2%)                                             
      Muscularis, Mineralization                                                 1 (2%)                                             
   Liver                                              (55)         (55)         (55)                                                
      Basophilic Focus                                11 (20%)     11 (20%)      6 (11%)                                            
      Clear Cell Focus                                 1 (2%)       7 (13%)      4 (7%)                                             
      Concretion                                       1 (2%)                                                                       
      Cytomegaly                                       2 (4%)       1 (2%)       3 (5%)                                             
      Degeneration, Cystic                            26 (47%)     23 (42%)     18 (33%)                                            
      Eosinophilic Focus                               4 (7%)       2 (4%)       1 (2%)                                             
      Fatty Change                                     5 (9%)       4 (7%)       4 (7%)                                             
      Focal Cellular Change                                         1 (2%)                                                          
      Hematocyst                                                    1 (2%)                                                          
      Hematopoietic Cell Proliferation                 2 (4%)       3 (5%)       1 (2%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page    9                                                              
NTP Experiment-Test: 05040-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:30  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Hepatodiaphragmatic Nodule                       6 (11%)     10 (18%)      9 (16%)                                            
      Hyperplasia, Focal                               1 (2%)                    1 (2%)                                             
      Hyperplasia, Multifocal                                       1 (2%)       1 (2%)                                             
      Inflammation, Chronic                           18 (33%)     19 (35%)     19 (35%)                                            
      Mixed Cell Focus                                 6 (11%)      2 (4%)                                                          
      Necrosis, Coagulative                            7 (13%)      4 (7%)       7 (13%)                                            
      Necrosis, Coagulative, Multifocal                                          1 (2%)                                             
      Arteriole, Inflammation, Proliferative                                     3 (5%)                                             
      Arteriole, Thrombosis                                                      2 (4%)                                             
      Bile Duct, Dilatation                            1 (2%)                                                                       
      Bile Duct, Hyperplasia                          54 (98%)     52 (95%)     54 (98%)                                            
      Centrilobular, Atrophy                           5 (9%)       8 (15%)     10 (18%)                                            
      Serosa, Fibrosis, Focal                          1 (2%)                                                                       
      Serosa, Inflammation, Chronic                                 1 (2%)                                                          
      Sinusoid, Dilatation                             2 (4%)       7 (13%)      4 (7%)                                             
      Vein, Dilatation                                              1 (2%)                                                          
   Mesentery                                          (12)         (16)         (9)                                                 
      Accessory Spleen                                              3 (19%)                                                         
      Fat, Inflammation, Chronic                       4 (33%)      3 (19%)                                                         
      Fat, Inflammation, Granulomatous                 1 (8%)                                                                       
      Fat, Mineralization                              1 (8%)                                                                       
      Fat, Necrosis                                    3 (25%)      1 (6%)       2 (22%)                                            
      Lymphatic, Ectasia                               1 (8%)                                                                       
   Pancreas                                           (53)         (36)         (54)                                                
      Atrophy                                          6 (11%)      6 (17%)      5 (9%)                                             
      Hyperplasia, Nodular                             1 (2%)       1 (3%)                                                          
      Inflammation, Chronic                            1 (2%)                                                                       
      Acinus, Hyperplasia                              1 (2%)                                                                       
      Arteriole, Inflammation, Chronic                 1 (2%)                                                                       
      Duct, Inflammation, Chronic                      1 (2%)                    1 (2%)                                             
   Pharynx                                            (1)                                                                           
      Abscess                                          1 (100%)                                                                     
   Salivary Glands                                    (54)         (37)         (55)                                                
      Atrophy, Focal                                                             1 (2%)                                             
      Cytoplasmic Alteration                           2 (4%)       1 (3%)                                                          
      Hyperplasia                                                   1 (3%)                                                          
      Duct, Hyperplasia                                1 (2%)                                                                       
      Duct, Inflammation, Chronic                     15 (28%)      3 (8%)       5 (9%)                                             
      Duct, Metaplasia, Squamous                      12 (22%)      2 (5%)       6 (11%)                                            
   Stomach, Forestomach                               (55)         (36)         (55)                                                
      Abscess                                                       1 (3%)                                                          
      Acanthosis                                       3 (5%)                    2 (4%)                                             
      Edema                                            1 (2%)                                                                       
      Hemorrhage                                                    1 (3%)                                                          
      Hyperkeratosis                                   2 (4%)                    2 (4%)                                             
      Hyperplasia, Papillary                           3 (5%)       2 (6%)       1 (2%)                                             
      Inflammation, Chronic                            4 (7%)       1 (3%)       1 (2%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   10                                                              
NTP Experiment-Test: 05040-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:30  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - CONT                                                                                                            
      Ulcer                                            1 (2%)       3 (8%)       1 (2%)                                             
      Ulcer, Chronic                                                1 (3%)                                                          
      Epithelium, Degeneration, Ballooning             1 (2%)                                                                       
      Muscularis, Mineralization                                                 4 (7%)                                             
   Stomach, Glandular                                 (54)         (34)         (55)                                                
      Erosion                                                       1 (3%)                                                          
      Inflammation, Acute                                           1 (3%)                                                          
      Inflammation, Chronic                                         1 (3%)       1 (2%)                                             
      Mineralization                                                             5 (9%)                                             
      Ulcer                                                         1 (3%)       1 (2%)                                             
   Tooth                                              (8)          (9)          (10)                                                
      Pulp, Proliferation Connective Tissue, Focal                               1 (10%)                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (55)         (38)         (55)                                                
      Cardiomyopathy                                  46 (84%)     28 (74%)     47 (85%)                                            
      Mineralization                                   1 (2%)                    7 (13%)                                            
      Thrombosis                                                    1 (3%)                                                          
      Atrium, Dilatation                                                         1 (2%)                                             
      Atrium, Thrombosis                               4 (7%)       5 (13%)      4 (7%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Gland, Cortex                              (54)         (37)         (54)                                                
      Accessory Adrenal Cortical Nodule                                          1 (2%)                                             
      Angiectasis                                      1 (2%)                    1 (2%)                                             
      Cyst                                             1 (2%)                                                                       
      Degeneration, Fatty, Focal                       6 (11%)      4 (11%)      6 (11%)                                            
      Hyperplasia                                      7 (13%)      4 (11%)     11 (20%)                                            
      Necrosis, Coagulative                                         1 (3%)                                                          
      Vacuolization Cytoplasmic                        5 (9%)       7 (19%)      7 (13%)                                            
      Capsule, Hyperplasia                                          1 (3%)       1 (2%)                                             
   Adrenal Gland, Medulla                             (55)         (48)         (55)                                                
      Atrophy                                                       1 (2%)                                                          
      Fibrosis                                                      1 (2%)                                                          
      Hematopoietic Cell Proliferation                 1 (2%)                                                                       
      Hyperplasia                                     19 (35%)     19 (40%)     22 (40%)                                            
      Mineralization                                                1 (2%)                                                          
   Islets, Pancreatic                                 (54)         (36)         (54)                                                
      Hyperplasia                                      3 (6%)       2 (6%)                                                          
   Parathyroid Gland                                  (54)         (36)         (54)                                                
      Cyst                                                                       1 (2%)                                             
      Hyperplasia                                     13 (24%)      6 (17%)     19 (35%)                                            
   Pituitary Gland                                    (54)         (54)         (54)                                                
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   11                                                              
NTP Experiment-Test: 05040-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:30  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - CONT                                                                                                             
      Pars Distalis, Cyst                              7 (13%)      8 (15%)      7 (13%)                                            
      Pars Distalis, Fibrosis                          1 (2%)                                                                       
      Pars Distalis, Hemorrhage                                     1 (2%)                                                          
      Pars Distalis, Hyperplasia                      12 (22%)     14 (26%)     11 (20%)                                            
      Pars Distalis, Necrosis                          1 (2%)       1 (2%)                                                          
      Pars Intermedia, Cyst                            1 (2%)                                                                       
   Thyroid Gland                                      (55)         (38)         (55)                                                
      Ultimobranchial Cyst                             2 (4%)                    1 (2%)                                             
      C-Cell, Hyperplasia                              4 (7%)       5 (13%)      7 (13%)                                            
      Follicle, Cyst                                                1 (3%)                                                          
      Follicular Cell, Hyperplasia                     1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Coagulating Gland                                               (1)          (2)                                                 
      Inflammation, Chronic                                                      1 (50%)                                            
      Inflammation, Suppurative                                     1 (100%)                                                        
   Epididymis                                         (53)         (37)         (55)                                                
      Degeneration, Mucoid                             1 (2%)                    4 (7%)                                             
      Inflammation, Chronic                            1 (2%)                                                                       
   Preputial Gland                                    (53)         (34)         (54)                                                
      Abscess                                          1 (2%)       1 (3%)       1 (2%)                                             
      Cyst                                             5 (9%)       2 (6%)       7 (13%)                                            
      Hyperplasia                                      2 (4%)       1 (3%)       1 (2%)                                             
      Inflammation, Chronic                           12 (23%)     13 (38%)     13 (24%)                                            
      Inflammation, Suppurative                        5 (9%)       2 (6%)       1 (2%)                                             
      Necrosis, Coagulative                                                      1 (2%)                                             
      Pigmentation, Hemosiderin                                                  2 (4%)                                             
   Prostate                                           (53)         (41)         (55)                                                
      Abscess                                                       1 (2%)       1 (2%)                                             
      Hemorrhage                                                    1 (2%)                                                          
      Hyperplasia                                      3 (6%)       4 (10%)      4 (7%)                                             
      Hyperplasia, Focal                                            1 (2%)                                                          
      Inflammation, Chronic                            7 (13%)      1 (2%)       5 (9%)                                             
      Inflammation, Suppurative                        9 (17%)      8 (20%)     13 (24%)                                            
   Seminal Vesicle                                    (53)         (36)         (55)                                                
      Inflammation, Chronic                            1 (2%)                                                                       
      Mineralization                                                             1 (2%)                                             
   Testes                                             (54)         (54)         (55)                                                
      Atrophy                                         39 (72%)     31 (57%)     35 (64%)                                            
      Cyst                                                          1 (2%)       1 (2%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   12                                                              
NTP Experiment-Test: 05040-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:30  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - CONT                                                                                                               
      Bilateral, Interstitial Cell, Hyperplasia                     1 (2%)                                                          
      Interstitial Cell, Hyperplasia                  11 (20%)      7 (13%)      7 (13%)                                            
      Seminiferous Tubule, Degeneration, Cystic                                  1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Blood                                              (22)         (25)         (29)                                                
      Anemia                                                        2 (8%)                                                          
      Hypersegmentation                                             1 (4%)                                                          
      Left Shift                                       1 (5%)                                                                       
      Neutrophilia                                     2 (9%)       3 (12%)      1 (3%)                                             
      Thrombocytopenia                                 1 (5%)       2 (8%)                                                          
   Bone Marrow                                        (55)         (37)         (55)                                                
      Depletion Cellular                                            1 (3%)                                                          
      Myelofibrosis                                                 2 (5%)       3 (5%)                                             
      Erythroid Cell, Hyperplasia                                                2 (4%)                                             
      Myeloid Cell, Hyperplasia                        1 (2%)       3 (8%)       3 (5%)                                             
   Lymph Node                                         (55)         (41)         (55)                                                
      Bronchial, Pigmentation, Hemosiderin                          1 (2%)                                                          
      Bronchial, Sinus, Ectasia                        1 (2%)       1 (2%)                                                          
      Cortex, Mediastinal, Atrophy                                               1 (2%)                                             
      Iliac, Hyperplasia, Plasma Cell                                            1 (2%)                                             
      Iliac, Sinus, Ectasia                                         1 (2%)       1 (2%)                                             
      Inguinal, Hyperplasia, Lymphoid                                            1 (2%)                                             
      Inguinal, Hyperplasia, Plasma Cell               1 (2%)       1 (2%)       2 (4%)                                             
      Inguinal, Sinus, Ectasia                         1 (2%)                    1 (2%)                                             
      Lumbar, Hyperplasia, Macrophage                               1 (2%)                                                          
      Lumbar, Hyperplasia, Plasma Cell                              1 (2%)       1 (2%)                                             
      Lumbar, Pigmentation, Hemosiderin                             1 (2%)                                                          
      Lumbar, Sinus, Ectasia                                        2 (5%)                                                          
      Mediastinal, Hyperplasia, Macrophage             2 (4%)       1 (2%)       1 (2%)                                             
      Mediastinal, Hyperplasia, Plasma Cell                         1 (2%)       1 (2%)                                             
      Mediastinal, Pigmentation, Hemosiderin           1 (2%)                    1 (2%)                                             
      Mediastinal, Sinus, Ectasia                      1 (2%)       2 (5%)       3 (5%)                                             
      Pancreatic, Hyperplasia, Macrophage              1 (2%)                                                                       
      Pancreatic, Sinus, Ectasia                       2 (4%)       1 (2%)                                                          
      Renal, Pigmentation, Hemosiderin                                           1 (2%)                                             
      Renal, Sinus, Ectasia                            1 (2%)       1 (2%)                                                          
   Lymph Node, Mandibular                             (52)         (38)         (54)                                                
      Congestion                                       1 (2%)                                                                       
      Hyperplasia, Lymphoid                                         1 (3%)                                                          
      Hyperplasia, Plasma Cell                         2 (4%)       4 (11%)      3 (6%)                                             
      Sinus, Ectasia                                   7 (13%)      3 (8%)       4 (7%)                                             
   Lymph Node, Mesenteric                             (53)         (38)         (54)                                                
      Congestion                                       1 (2%)                                                                       
      Depletion Lymphoid                                            2 (5%)       1 (2%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   13                                                              
NTP Experiment-Test: 05040-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:30  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - CONT                                                                                                         
      Hyperplasia, Macrophage                          2 (4%)       3 (8%)       1 (2%)                                             
      Hyperplasia, Plasma Cell                         3 (6%)                    1 (2%)                                             
      Pigmentation, Hemosiderin                        1 (2%)                                                                       
      Sinus, Ectasia                                   9 (17%)      5 (13%)      3 (6%)                                             
   Spleen                                             (55)         (52)         (55)                                                
      Fibrosis                                         7 (13%)      5 (10%)      8 (15%)                                            
      Hematopoietic Cell Proliferation                 3 (5%)       5 (10%)      3 (5%)                                             
      Hemorrhage                                       1 (2%)                                                                       
      Hyperplasia, Macrophage                          1 (2%)                    1 (2%)                                             
      Capsule, Infarct                                              1 (2%)                                                          
      Capsule, Inflammation, Chronic                                1 (2%)                                                          
      Red Pulp, Depletion Cellular                                               1 (2%)                                             
   Thymus                                             (46)         (35)         (46)                                                
      Congestion                                                                 1 (2%)                                             
      Cyst                                             1 (2%)       1 (3%)       2 (4%)                                             
      Inflammation                                                  1 (3%)                                                          
      Epithelial Cell, Hyperplasia                     1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (49)         (29)         (53)                                                
      Cyst                                                                       1 (2%)                                             
      Hyperplasia                                     14 (29%)      8 (28%)     10 (19%)                                            
      Mineralization                                                             1 (2%)                                             
   Skin                                               (55)         (37)         (54)                                                
      Abscess                                                                    1 (2%)                                             
      Cyst Epithelial Inclusion                                     1 (3%)                                                          
      Inflammation, Chronic                            4 (7%)       2 (5%)       5 (9%)                                             
      Inflammation, Granulomatous                                   1 (3%)                                                          
      Inflammation, Suppurative                                                  1 (2%)                                             
      Inflammation, Proliferative                      1 (2%)                                                                       
      Ulcer                                            1 (2%)       6 (16%)      4 (7%)                                             
      Hindlimb, Subcutaneous Tissue, Right,                                                                                         
          Inflammation, Acute                                       1 (3%)                                                          
      Hindlimb, Right, Epidermis, Abscess, Multiple                 1 (3%)                                                          
      Hindlimb, Right, Epidermis, Degeneration,                                                                                     
           Ballooning                                               1 (3%)                                                          
      Scrotal, Inflammation, Suppurative                                         1 (2%)                                             
      Sebaceous Gland, Hyperplasia                                  1 (3%)                                                          
      Subcutaneous Tissue, Abscess                                               2 (4%)                                             
      Subcutaneous Tissue, Cyst                                     1 (3%)                                                          
      Subcutaneous Tissue, Edema                                                 1 (2%)                                             
      Subcutaneous Tissue, Hemorrhage                                            1 (2%)                                             
      Subcutaneous Tissue, Inflammation, Chronic       2 (4%)       1 (3%)                                                          
      Subcutaneous Tissue, Inflammation,                                                                                            
          Suppurative                                                            1 (2%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   14                                                              
NTP Experiment-Test: 05040-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:30  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (55)         (37)         (55)                                                
      Fibrous Osteodystrophy                                                     1 (2%)                                             
      Inflammation, Chronic Active                                  1 (3%)                                                          
   Skeletal Muscle                                    (4)          (3)          (6)                                                 
      Degeneration                                                               1 (17%)                                            
      Inflammation, Chronic                            1 (25%)                                                                      
      Mineralization                                                             1 (17%)                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (55)         (37)         (55)                                                
      Compression                                      4 (7%)       2 (5%)       3 (5%)                                             
      Cerebellum, Embolus Tumor                                     1 (3%)                                                          
      Cerebellum, Infarct                                           1 (3%)                                                          
      Choroid Plexus, Inflammation, Chronic                         1 (3%)                                                          
      Ventricle, Dilatation                                         1 (3%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (1)                       (1)                                                 
      Hemorrhage                                                                 1 (100%)                                           
      Inflammation, Chronic                            1 (100%)                                                                     
   Lung                                               (55)         (38)         (55)                                                
      Atelectasis                                                                1 (2%)                                             
      Congestion                                       2 (4%)       1 (3%)                                                          
      Crystals                                                                   1 (2%)                                             
      Hemorrhage                                                    1 (3%)       3 (5%)                                             
      Hyperplasia, Macrophage                          7 (13%)      2 (5%)       6 (11%)                                            
      Hyperplasia, Adenomatous                         3 (5%)       2 (5%)       1 (2%)                                             
      Inflammation, Acute                              1 (2%)                                                                       
      Inflammation, Granulomatous                      1 (2%)                                                                       
      Inflammation, Suppurative                                                  1 (2%)                                             
      Mineralization                                                             2 (4%)                                             
      Necrosis, Coagulative                            1 (2%)                                                                       
      Necrosis, Liquifactive                                                     1 (2%)                                             
      Proliferation Connective Tissue                                            1 (2%)                                             
      Arteriole, Thrombosis                                                      2 (4%)                                             
      Arteriole, Media, Hyperplasia                                 1 (3%)                                                          
      Bronchiole, Foreign Body                         1 (2%)                                                                       
      Interstitium, Fibrosis                                                     1 (2%)                                             
      Interstitium, Inflammation, Chronic              4 (7%)       2 (5%)       1 (2%)                                             
      Pleura, Inflammation, Chronic                    4 (7%)                    2 (4%)                                             
   Nose                                               (55)         (37)         (55)                                                
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   15                                                              
NTP Experiment-Test: 05040-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:30  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - CONT                                                                                                           
      Inflammation, Chronic                            8 (15%)      7 (19%)      6 (11%)                                            
      Inflammation, Suppurative                        1 (2%)                    2 (4%)                                             
      Metaplasia, Squamous                                          1 (3%)                                                          
      Nasolacrimal Duct, Inflammation, Chronic        27 (49%)     21 (57%)     34 (62%)                                            
      Nasolacrimal Duct, Inflammation, Suppurative     3 (5%)       2 (5%)       2 (4%)                                             
      Nasolacrimal Duct, Metaplasia, Squamous         45 (82%)     24 (65%)     47 (85%)                                            
      Respiratory Epithelium, Cyst                                  1 (3%)                                                          
   Trachea                                            (53)         (37)         (55)                                                
      Exudate                                          1 (2%)                                                                       
      Inflammation, Chronic                            3 (6%)       1 (3%)       1 (2%)                                             
      Glands, Cyst                                     4 (8%)                    2 (4%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Ear                                                (2)          (2)                                                              
      Exudate                                                       1 (50%)                                                         
      Middle Ear, Inflammation, Suppurative            1 (50%)                                                                      
   Eye                                                (2)          (3)          (4)                                                 
      Hemorrhage                                                    1 (33%)                                                         
      Synechia                                                      2 (67%)                                                         
      Cornea, Inflammation, Subacute                                             1 (25%)                                            
      Cornea, Necrosis                                                           1 (25%)                                            
      Cornea, Proliferation                                         1 (33%)                                                         
      Retina, Atrophy                                               3 (100%)     2 (50%)                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (55)         (55)         (55)                                                
      Cyst                                                          2 (4%)       6 (11%)                                            
      Hemorrhage                                                                 1 (2%)                                             
      Infarct                                          1 (2%)       1 (2%)                                                          
      Inflammation, Chronic                           27 (49%)     30 (55%)     27 (49%)                                            
      Mineralization                                   1 (2%)                                                                       
      Necrosis, Coagulative                            1 (2%)                                                                       
      Nephropathy                                     53 (96%)     52 (95%)     55 (100%)                                           
      Pelvis, Hematopoietic Cell Proliferation                      1 (2%)                                                          
      Pelvis, Inflammation, Suppurative                                          1 (2%)                                             
      Renal Tubule, Hyperplasia                                                  1 (2%)                                             
      Renal Tubule, Hyperplasia, Focal                                           1 (2%)                                             
      Renal Tubule, Inflammation, Suppurative          4 (7%)       7 (13%)                                                         
      Transitional Epithelium, Hyperplasia,                                                                                         
          Papillary                                    1 (2%)       6 (11%)      5 (9%)                                             
   Urinary Bladder                                    (51)         (37)         (55)                                                
      Hyperplasia, Papillary                                        1 (3%)                                                          
      Inflammation, Chronic                            7 (14%)      1 (3%)       3 (5%)                                             
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   16                                                              
NTP Experiment-Test: 05040-01         INCIDENCE RATES OF NONNEOPLASTIC LESIONS BY ANATOMIC SITE (a)               Report: PEIRPT03
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:30  
____________________________________________________________________________________________________________________________________
         FISCHER 344 RATS MALE                     VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
URINARY SYSTEM - CONT                                                                                                               
      Inflammation, Chronic Active                                               1 (2%)                                             
      Submucosa, Edema                                                           1 (2%)                                             
                                                                                                                                    
a  Number of animals examined microscopically at site and number of animals with lesion                                             
                                                             Page   17                                                              
                             ------------------------------------------------------------                                           
                             ----------              END OF REPORT             ----------                                           
                             ------------------------------------------------------------                                           

--multipart-boundary
Content-type: text/plain
Range: bytes 111930-111930/111930


--multipart-boundary--