Decreased superovulation in adult mice following neonatal exposures to technical methoxychlor.
Eroschenko-VP; Swartz-WJ; Ford-LC
Reprod Toxicol 1997 Nov; 11(6):807-814
The effect of neonatal exposure to technical methoxychlor (72435) (MXC) on superovulation was examined. Neonatal female CD-1-mice were injected daily with 10 micrograms of 17-beta-estradiol or 0.1 to 1 milligram of technical MXC for 14 days. Controls received vehicle only. At 2 and 4 months of age, the mice were weighed and either sacrificed or injected with a superovulatory regimen of pregnant mare's serum gonadotropin or human chorionic gonadotropin. The mice were sacrificed 15 to 20 hours after superovulatory treatment. Ovulated oocytes were released from the uterine horns and examined microscopically. Ovaries were dissected and also examined microscopically. At 2 months of age, mice treated with 17- beta-estradiol had significantly higher body weight than controls. No significant differences in body weight were noted among the groups at 4 months of age. At 2 and 4 months, mean relative ovarian weights were significantly lower in mice treated with 17-beta- estradiol than in controls. At 4 months of age, ovarian weights were reduced significantly and dose dependently in MXC treated mice, compared to controls. Although treatment with the superovulatory gonadotropins increased mean relative ovarian weights, ovary weights were reduced dose dependently at 2 months in 17-beta-estradiol and MXC treated mice exposed to gonadotropins. At 4 months of age, the number of ovulated oocytes was significantly and dose dependently reduced in 17-beta-estradiol and MXC treated mice exposed to gonadotropins. Two and 4 month old mice exposed to 17-beta- estradiol or MXC without subsequent gonadotropin treatment lacked the numerous corpora lutea of control ovaries. Gonadotropin treatment induced ovulation in 17-beta-estradiol treated mice, as indicated by corpora lutea. The number of corpora lutea in MXC exposed mice was only slightly increased by gonadotropin treatment. The authors conclude that neonatal exposure to technical MXC inhibits ovulatory functions and renders mice less sensitive to gonadotropin stimulation.
NIOSH-Publication; NIOSH-Grant; Reproductive-system-disorders; Neonates; Pesticides; Reproductive-system; Reproductive-effects; Reproductive-hazards; Gonadotropic-hormones; Laboratory-animals
Anatomy Louisiana State University 1542 Tulane Avenue New Orleans, LA 70112
Louisiana State University, School of Medicine, Department of Anatomy, New Orleans, Louisiana