Methoxychlor given in the periimplantation period blocks sexual arousal inmale mice

To determine whether pesticide methoxychlor (MXC) alters sexual arousal in male offspring, pregnant ICR mice remained untreated or received daily subc utaneous injections (s.c.) of olive oil, 33.0 mg/kg bw purified (95%) MXC, or 0.33 mg/kg bw estradiol-17 beta in vehicle on Days 5 to 7 of pregnancy. Live births were recorded in all groups except the estradiol group. At 4 mo nths, untreated or olive oil-treated male offspring exhibited normal sexual arousal. When placed near a plastic partition with an estrus female behind it, these males spent significantly more time near the partition than near a vacant half of the cage and exhibited a sharp increase in plasma testost erone. MXC-exposed males showed no sexual arousal, spent much less time nea r the partition with an estrus female, and exhibited significantly lower pl asma testosterone levels. Exposure to purified MXC close to implantation al ters the function of the hypothalamic-pituitary-testicular axis and comprom ises male sexual behavior in offspring. (C) 1999 Elsevier Science Inc. All rights reserved.