Toxicology and Carcinogenesis Studies of 4-Vinylcyclohexene (CAS NO. 100-40-3) in F344/N Rats and B6C3F1 Mice (Gavage Studies)

摘要

Toxicology and carcinogenesis studies of 4-vinylcyclohexene (greater than 98% pure), a dimer of 1,3-butadiene present in the off-gases from tire curing, were conducted by administering the chemical in corn oil by gavage 5 days per week at doses of 0, 200, or 400 mg/kg body weight to groups of 50 F344/N rats and B6C3F1 mice of each sex for 103 weeks. Doses selected for the 2-year studies were based on survival, body weight gains, and histopathologic effects observed during the 14-day and 13-week studies. 4-Vinylcyclohexene was administered by gavage in corn oil to F344/N rats and B6C3F1 mice of each sex at doses of 200 or 400 mg/kg for 103 weeks. Under these conditions, the 2-year gavage studies of 4-vinylcyclohexene in male and female rats and male mice were considered inadequate studies of carcinogenicity because of extensive and early mortality at the high dose or at both doses and the lack of conclusive evidence of a carcinogenic effect. There was clear evidence of carcinogenicity of 4-vinylcyclohexene for female mice, as shown by markedly increased incidences of uncommon ovarian neoplasms at both doses. In addition, the increased incidence of adrenal gland adenomas in high dose female mice may have been related to the administration of 4-vinylcyclohexene.