Effects of methoxychlor on the reproductive system of the adult female mouse: 2. Ultrastructural observations.

The purpose of this study is to examine the effects of the pesticide methoxychlor (MXC) on the ultrastructural appearance of the different cellular components of the mouse ovary. Sexually mature (7- to 8-week) virgin female CD-1 mice were exposed to 5.0 mg MXC (50% technical grade) via oral gavage for 5 consecutive days each week for 4 weeks. Control groups received either 0.025 mg estradiol-17 beta (E-17 beta) or the sesame oil vehicle for the same time period. Twenty-four hours following the final exposure, animals were sacrificed. Ultrastructural observations revealed increased lipid accumulation in interstitial cells and theca cells of both estradiol-treated and 5.0 mg MXC-treated mice. This would suggest that these cells are unable to synthesize and secrete steroids. Thus, this commonly employed pesticide appears to closely mimic those effects on the female ovary induced by estrogen.