Saturday, November 26, 2011

Common pesticide may reduce fertility in women

Public release date: 12-Sep-2005
Contact: Karen N. Peart
Yale University
Common pesticide may reduce fertility in women
Methoxychlor (MXC), a common insect pesticide used on food crops, may interfere with proper development and function of the reproductive tract, leading to reduced fertility in women, researchers at Yale School of Medicine write in the August issue of Endocrinology.

The researchers found that MXC, which was manufactured as a safer replacement for the now-banned DDT, alters the estrogen-regulated gene Hoxa10 in the reproductive tract and reduces the ability of the uterus to support embryo implantation. The researchers used mice and then human cell lines to confirm their findings.

MXC is a man-made pesticide used to kill flies, mosquitoes, cockroaches and other insects, and is applied directly to food crops, livestock, home gardens and pets. It is one of a large number of chemicals that can mimic the action of hormones and in some instances interfere with endocrine function.

Some of these endocrine disruptors bind estrogen receptors and adversely affect reproductive tract development, which is heavily influenced by estrogen. MXC and other chemicals like DDT have been shown in other studies to induce abnormalities in tissue development and function in the female reproductive tract.

"MXC has an adverse effect on these mice similar to that of DES, a synthetic estrogen," said senior author Hugh S. Taylor, M.D., associate professor in the Division of Reproductive Endocrinology and Infertility in the Department of Obstetrics, Gynecology & Reproductive Sciences at Yale School of Medicine. "Female offspring of women exposed to DES were more likely to have an abnormally shaped cervix, were more prone to cancer of the vagina, miscarriages, early labor and other complications."

Other authors on the study included Xiaolan Fei and Hajin Chung


Public release date: 13-Mar-2000
Contact: Sandra Waldman
Population Council
Common pesticide product reduces testosterone levels

The chemical HPTE, a metabolite of the common pesticide methoxychlor, reduces testosterone production and could be a contributory factor in male infertility, Population Council scientists report in the March 2000 issue of Biology of Reproduction*. Methoxychlor-a pesticide in the DDT family-gained popularity after DDT was banned in the United States in 1972.

Matt Hardy and Benson Akingbemi have been investigating endocrine disruptors and their effects on the reproductive system. They examined the effect of HPTE on testosterone production in developing (progenitor and immature) and adult Leydig cells. The researchers found that the more HPTE that Leydig cells were exposed to, the less testosterone the cells produced. HPTE inhibited testosterone production in developing Leydig cells after ten hours of treatment, and in adult Leydig cells after 18 hours. Inhibition of Leydig cells was due to the down regulation of one of four enzymes that catalyze the reactions that occur during androgen biosynthesis.



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