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Study Information
Study Attribute Value
CEBS Accession Number: 002-01525-0014-0000-0
Chemical Name: 5,5-Diphenylhydantoin (phenytoin)
CASRN: 57-41-0
NTP Study Type: Genetic Toxicology - Rodent Cytogenetics
NTP Study ID: 252423_CA
Study Result: Negative

Test Type Start Date Sample Time (h) Species Sex Tissue Protocol Trend Test P
CA 04/04/85 17 Mouse Male Bone Marrow Intraperitoneal Injection x 1/study, 17 hour 0.1890
Test Group Dose
(mg/kg)		 n Percent Cells w/ Aberrations
(Mean ± SEM)		 Pairwise P
Positive Control Dimethylbenzanthracene 
100         
 8 6.50 ± 1.40 0.0001
Test Chemical 5,5-Diphenylhydantoin (phenytoin) 
125         
 8 0.75 ± 0.37 0.7614
  
250         
 8 0.75 ± 0.37 0.7614
  
500         
 8 1.75 ± 0.59 0.2804
Vehicle Control No Stressor 
 0         
 8 1.25 ± 0.65 0.0000


Test Type Start Date Sample Time (h) Species Sex Tissue Protocol Trend Test P
CA 07/29/87 36 Mouse Male Bone Marrow Intraperitoneal Injection x 1/study, 36 hour 0.6883
Test Group Dose
(mg/kg)		 n Percent Cells w/ Aberrations
(Mean ± SEM)		 Pairwise P
Positive Control Dimethylbenzanthracene 
100         
 8 25.00 ± 3.84 0.0000
Test Chemical 5,5-Diphenylhydantoin (phenytoin) 
37.5       
 8 0.25 ± 0.25 0.9994
  
75         
 8 3.50 ± 1.92 0.4224
  
150         
 8 1.75 ± 0.70 0.9129
Vehicle Control No Stressor 
 0         
 8 3.25 ± 0.92 0.0000


Footnotes:
IP/IJ: Intraperitoneal Injection
INHAL: Inhalation
n: Number of animals analyzed