Assessment of Follicle Destruction in Chemical-Induced Ovarian Toxicity

The ovary plays a pivotal role in the regulation of reproductive function in females. Development, maturation, and ovulation of oocytes occur within ovarian follicles. Females are born with a finite number of undeveloped, primordial follicles. Chemicals that destroy oocytes contained in these follicles can produce premature ovarian failure (menopause) because once a primordial follicle is destroyed, it cannot be replaced. This article focuses on chemicals that have been shown to destroy these small follicles in laboratory animals. An ovotoxic compound of particular interest is 4-vinylcyclohexene (VCH) and its epoxide metabolites. The specific information discussed here relates to various aspects of VCH-inuced ovarian toxicity. This includes species specificity, disposition and metabolism, direct follicular effects, bioactivity of metabolites, and long-term responses to exposure. Using these studies as a model approach, a method for evaluation of the ovotoxic potential of other chemicals can be designed.