Another Emasculating Pesticide Found
Exposure in the womb to any of several chemicals can derail the normal sexual and behavioral development of male animals. Most of the agents scientists have identified as possessing this capacity--such as dioxin (SN: 5/30/92, p.359)--appear to exert their gender-bending properties by mimicking the actions of estrogen, a female sex hormone (SN: 1/8/94, p.24). But as described in the June TOXICOLOGY AND APPLIED PHARMACOLOGY, such changes also can result when a chemical blocks the activity of androgens, or male sex hormones.
A team of North Carolina-based researchers administered vinclozolin -- a systemic fungicide used to protect fruits, vegetables, ornamental plants, and turf -- to pregnant rats. Daily exposures of up to 200 milligrams per kilogram of body weight occurred from the 14th day of pregnancy through the third day following the birth of each rat's litter.
Year-old male offspring exhibited a range of reproductive abnormalities. Effects witnessed in those exposed to the highest doses included undescended testes, a cleft phallus, infertility, and hypospadias (a partially unfused phallus). The males also developed a "vaginal pouch" -- a structure characteristic of the female reproductive tract. Overall, the most-exposed animals suffered not only demasculinization, but also feminization, explains L. Earl Gray Jr. …