Effects of methoxychlor exposure during perinatal period on reproductive function after maturation in rats.

Methoxychlor (MXC) is a non-steroidal pesticide that is known to possess estrogenic activity, and therefore may be potentially hazardous to the development and/or reproduction. The present study assessed the effects of perinatal exposure to MXC on reproductive function after maturation in both male and female rats. Pregnant rats were fed a phytoestrogen-free diet containing different doses of MXC (24, 240, and 1200 ppm) from day 15 of gestation to day 10 after parturition, and reproductive functions of offspring were examined after maturation. In males, MXC exposure during the perinatal period decreased serum LH and FSH, but not testosterone levels, but it did not affect copulatory behavior. In females, MXC exposure prolonged the days exhibiting cornified vaginal smears during the estrous cycle. In addition, both the lordosis reflex and preovulatory LH surge on the presumptive proestrous evening were suppressed in MXC-exposed females. These results suggest that perinatal exposure to MXC exerts permanent effects on several aspects of the reproductive function in both male and female rats.