The following abstract presents results of a study conducted by a contract laboratory for the National Toxicology Program. The findings were not evaluated in accordance with the levels of evidence for reproductive or developmental criteria established by NTP in March 2009. The findings and conclusions for this study should not be construed to represent the views of NTP or the U.S. Government.
4-Vinylcyclohexene (VCH) was evaluated for reproductive toxicity in CD-1 mice using a continuous breeding protocol. VCH was administered to the animals by gavage in corn oil at doses of 0, 100, 250, or 500 mg/kg/day. Exposure to VCH for 14 weeks did not significantly affect measures of reproductive competence. including initial fertility. mean number of litters per pair, live litter size. the proportion of pups born alive. or adjusted live pup weight. Absolute live pup weight was decreased (males and sexes combined) at the high dose. F0 feed and water consumption were not adversely affected by treatment. At necropsy, the F0 females in the high-dose group had slightly decreased body weight.
VCH did not adversely affect preweaning growth or survival in the F1 generation. High-dose (500 mg/kg/day VCH) males, selected on postnatal day 21 for inclusion in Task 4, had decreased body weight throughout Task 4 to scheduled necropsy. F1 females selected from the high-dose group for inclusion in Task 4 had decreased body weight beginning at 74±10 days of age through Task 4 to necropsy. There was no effect of VCH treatment on feed or water consumption. VCH had no effect on the reproductive competence of the F1 generation; adjusted live pup weight for females and the sexes combined was slightly but significantly depressed in the VCH-treated litters. At necropsy, relative, but not absolute, liver weight (males and females) and sperm motility were increased in the VCH-treated group; testicular spermatid count was decreased by VCH treatment. The number of primordial, growing. and antral oocytes was significantly reduced in VCH-treated females.
VCH at doses up to 500 mg/kg/day had no significant adverse effect on reproductive competence in either the F0 or F1 generation. For the F1 males and females. this was in spite of a slight but significant reduction in spermatid head count (83% of control) and ovarian follicles (46-67% of control), respectively. F0 females receiving 500 mg/kg/day exhibited slight general toxicity manifested as an 8% decrease in body weight after 18 weeks treatment. F1 males and females receiving 500 mg/kg/day VCH exhibited generalized toxicity manifested as an 8-10% decrease in body weight throughout Task 4. These data indicate that VCH did not cause a detectable decrease in reproductive competence in the F0 generation, nor was reproductive function adversely affected in F1 mice at doses that caused decreased body weight and ovarian and testicular toxicity.
NTIS # PB91211250