Abstract |
The estrogenic pesticide methoxychlor (MXC) is known to compromise implantation, and, in previous work, this reduction in fertility has been attributed to a direct effect on uterine function. The present study was designed to investigate the effect of MXC on embryo transport rate, another phenomenon that is vulnerable to estrogenic effects. A range of doses of MXC was administered to groups of rats during Days 1-3 of pregnancy (Day 0 = sperm positive), and the distribution of embryos in the oviducts and uteri of animals was assessed at five times intervals prior to implantation. No effect of MXC was detected by the afternoon of Day 1. On days 2 and 3, 200 and 500 mg/kg/day MXC accelerated embryo transport into the uterus, while the 500 mg/kg/day dosage also reduced the total recovery of embryos. At this time, most control embryos remained in the oviduct. On third day, 100 mg/kg/day MXC also accelerated embryo transport to the uterus. These data demonstrate that MXC produces a dose-dependent acceleration of embryo transport through the female reproductive tract. (Copyright (c) 1990 Academic Press, Inc.) |