Bioassay of 3-sulfolene for possible carcinogenicity (CAS No. 77-79-2)

A bioassay of 3-sulfolene for possible carcinogenicity was conducted using Osborne-Mendel rats and B6C3F1 mice. 3-Sulfolene in corn oil was administered by gavage, at either of two dosages, to groups of 50 male and 50 female animals of each species. The 78-week period of chemical administration was followed by an observation period of 33 weeks for the high dose female rats and low dose rats of both sexes. The last high dose male rat died in week 60. All treated groups of mice were observed for an additional 13 weeks following chemical administration. Initial dosage levels for the chronic bioassay were selected on the basis of a preliminary subchronic toxicity test. Subsequent dosage adjustments were made during the course of the chronic bioassay. The time-weighted average high and low doses of 3-sulfolene in the chronic study were respectively, 372 and 197 mg/kg/day for male rats, 240 and 120 mg/kg/day for female rats, 622 and 311 mg/kg/day for male mice and 768 and 384 mg/kg/day for the female mice. For each species, 20 animals of each sex were placed on test as vehicle controls. These animals were gavaged with corn oil at the same time that dosed animals were gavaged with the 3-sulfolene mixtures. Twenty animals of each sex were placed on test as untreated controls for each species. These animals were not intubated. There was a significant positive association between the administered dosages of 3-sulfolene and mortality in both sexes of rats and mice. In all groups, except the high dose male rats and the high dose male and female mice, adequate numbers of animals survived sufficiently long to be at risk from late-developing tumors. There were no tumors in either sex of rats or mice for which a significant positive association could be established between chemical administration and incidence. Under the conditions of this bioassay, there was no evidence for the carcinogenicity of 3-sulfolene to Osborne-Mendel rats or B6C3F1 mice.