Long term reproductive organ and gonadotropin changes in female B6C3F1 mice following administration of the ovotoxin 4-vinylcyclohexene

Abstract

4-Vinylcyclohexene (VCH) is released during rubber manufacture as an environmental contaminant. It causes destruction of ovarian follicles and ovarian cancer in mice. To determine its long term effects on the female reproductive system, female B6C3F1 mice were administered sesame seed oil or VCH (800 mg/kg) ip daily for 30 days. Mice were killed when in diestrus at 30, 60, 120, 240, or 360 days after VCH administration. Ovaries and uteri were weighed and ovaries prepared for histology. Primary and secondary follicles were counted and FSH determined by RIA. The number of estrous cycles differed from controls in the 30 day group. Uterine weight differed in the 30, 60, and 360 day groups. Primary follicles, secondary follicles and ovarian weight decreased in the VCH groups. FSH increased in the 240 and 360 day VCH groups. These studies indicate that VCH causes a dramatic and permanent reduction in ovarian follicles with a reduction in ovarian weight the most obvious indicator of follicle destruction.