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Study Information
Study Attribute Value
CEBS Accession Number: 002-01525-0004-0000-9
Chemical Name: 5,5-Diphenylhydantoin (phenytoin)
CASRN: 57-41-0
NTP Study Type: Genetic Toxicology - Micronucleus
NTP Study ID: 252424
Strain and Species: B6C3F1 Mouse
Study Result: Male: Negative

Bone Marrow

Start Date Sample Collection Time Sex Cell Methodology Used Dosing Regimen Route Trend Test P-Value
1988-10-04 24 hour Male PCE Slide Scoring Intraperitoneal Injection x 3, 72 hour Intraperitoneal Injection 0.171
  Dose (mg/kg) Number of Animals Scored Mean MN-PCE/1000 PCE ± SEM Pairwise P
Vehicle Control Corn Oil 
 0         
 5 2.300 ± 0.980
Test Chemical 5,5-Diphenylhydantoin (phenytoin) 
17.5       
 5 2.800 ± 0.410 0.327 
35         
 4 3.630 ± 0.850 0.146 
70         
 5 3.400 ± 1.030 0.175
Positive Control Dimethylbenzanthracene 
12.5       
 5 7.300 ± 0.940 Value less than 0.0001

Start Date Sample Collection Time Sex Cell Methodology Used Dosing Regimen Route Trend Test P-Value
1988-10-04 24 hour Male PCE Slide Scoring Intraperitoneal Injection x 3, 72 hour Intraperitoneal Injection
  Dose (mg/kg) Number of Animals Scored Mean Percent PCE ± SEM Pairwise P
Vehicle Control Corn Oil 
 0         
 5 56.000 ± 3.270
Test Chemical 5,5-Diphenylhydantoin (phenytoin) 
17.5       
 5 49.700 ± 2.690 
35         
 4 51.000 ± 3.720 
70         
 5 47.100 ± 3.920
Positive Control Dimethylbenzanthracene 
12.5       
 5 39.000 ± 4.290

Blood

Start Date Sample Collection Time Sex Cell Methodology Used Dosing Regimen Route Trend Test P-Value
1988-10-04 24 hour Male PCE Slide Scoring Intraperitoneal Injection x 3, 72 hour Intraperitoneal Injection 0.800
  Dose (mg/kg) Number of Animals Scored Mean MN-PCE/1000 PCE ± SEM Pairwise P
Vehicle Control Corn Oil 
 0         
 5 3.200 ± 0.200
Test Chemical 5,5-Diphenylhydantoin (phenytoin) 
17.5       
 5 3.200 ± 0.300 0.500 
35         
 4 2.250 ± 0.430 0.886 
70         
 5 2.700 ± 0.440 0.743
Positive Control Dimethylbenzanthracene 
12.5       
 5 9.500 ± 1.290 Value less than 0.0001

Start Date Sample Collection Time Sex Cell Methodology Used Dosing Regimen Route Trend Test P-Value
1988-10-04 24 hour Male PCE Slide Scoring Intraperitoneal Injection x 3, 72 hour Intraperitoneal Injection
  Dose (mg/kg) Number of Animals Scored Mean Percent PCE ± SEM Pairwise P
Vehicle Control Corn Oil 
 0         
 5 3.240 ± 0.570
Test Chemical 5,5-Diphenylhydantoin (phenytoin) 
17.5       
 5 3.640 ± 0.330 
35         
 4 3.080 ± 0.260 
70         
 5 3.620 ± 0.270
Positive Control Dimethylbenzanthracene 
12.5       
 5 1.500 ± 0.320