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https://ntp.niehs.nih.gov/go/10979

5,5-Diphenylhydantoin (phenytoin): Target Organs and Levels of Evidence for TR-404

Toxicology and Carcinogenesis Studies of 5,5-Diphenylhydantoin (Phenytoin) (CASRN 57-41-0) in F344/N Rats and B6C3F1 Mice (Feed Studies)

Chemical (Study Title)
CASRN		Peer Review DateRoute/Exposure LevelsStudy Laboratory
5,5-Diphenylhydantoin (phenytoin)
57-41-0		06/24/1992Dosed-Feed
R: 0,240,800,2400, MM: 0,30,100,300, FM: 0,60,200,600 PPM/50 PER GROUP		Battelle Columbus Laboratory

Levels of Evidence

Male Rats: Equivocal Evidence
TypeOrgan/Tissue (Lesion)
Neoplastic Lesions
  • Liver: ADENOMA 0/50 1/50 4/50; CARCINOMA 0/50 1/50 0/50
Non-Neoplastic Lesions
  • LIVER: CENTRILOBULAR HYPERTROPHY
Other Considerations
  • LIVER: BASOPHILIC FOCUS 17/50 15/50 4/50
Female Rats: No Evidence
TypeOrgan/Tissue (Lesion)
Non-Neoplastic Lesions
  • LIVER: CENTRILOBULAR HYPERTROPHY
Other Considerations
  • LIVER: BASOPHILIC FOCUS 40/50 33/50 6/50
Male Mice: No Evidence
Female Mice: Clear Evidence
TypeOrgan/Tissue (Lesion)
Neoplastic Lesions
  • Liver: ADENOMA 5/48 13/49 22/50, HEPATOBLASTOMA OR CARCINOMA 0/48 1/49 12/50, COMBINED 5/48 14/49 30/50
Non-Neoplastic Lesions
  • LIVER: CENTRILOBULAR HYPERTROPHY