Toxicology and Carcinogenesis Studies of Phenylbutazone (Cas No. 50-33-9) in F344/N Rats and B6C3F1 Mice (Gavage Studies)

摘要

Two-year toxicology and carcinogenesis studies were conducted by administering 0, 50, or 100 mg/kg phenylbutazone in corn oil by gavage to groups of 50 rats of each sex, 5 days per week for 103 weeks. The doses administered to groups of 50 mice of each sex on the same schedule were 0, 150, or 300 mg/kg. Under the conditions of these 2-year studies, there was equivocal evidence of carcinogenic activity of phenylbutazone for male F344/N rats, as shown by the occurrence of small numbers of renal tubular cell adenomas and carcinomas. There was some evidence of carcinogenic activity for female F344/N rats, as shown primarily by the occurrence of two rare renal transitional cell carcinomas in the top dose group; none has ever been seen in vehicle control or untreated control female rats. Tubular cell adenomas may have been associated with the administration of phenylbutazone to female rats. There was some evidence of carcinogenic activity for male B6C3F1 mice, as shown by the increased incidence of hepatocellular adenomas or carcinomas (combined). There was no evidence of carcinogenic activity for female B6C3F1 mice administered phenylbutazone in corn oil at doses of 150 or 300 mg/kg.