National Toxicology Program

National Toxicology Program
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--
NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.