Gay frgogs

Frontiers: A Journal of Women Studies

Press Releases. Image Downloads. Popular weed killer gay frgogs frogs, disrupts their sexual development, UC Berkeley study shows 04 April By Robert Sanders, Media Relations. A restricted herbicide, atrazine is used primarily on crops, not around the home, and can be purchased and applied only by certified applicators.

Hayes, associate professor of integrative biology, and his colleagues report that atrazine at levels often found in the environment demasculinizes tadpoles and turns them into hermaphrodites - creatures with both male and female sexual characteristics. The herbicide also lowers levels of the male hormone testosterone in sexually mature male frogs by a factor of 10, to levels lower than those in normal female frogs.

As Hayes later discovered, many atrazine-contaminated ponds in the Midwest contain native leopard frogs with the same abnormalities. Abnormal gonads in a male Xenopus frog, the result of exposure to the herbicide atrazine. The frog has become a hermaphrodite, that is, it has both male testes and female ovaries sex organs.

High-resolution image available for download. It is unclear whether these abnormalities lead to reduced fertility. Hayes now is trying to determine how the abnormalities affect the frogs' ability to produce offspring. Because the herbicide has been in use for 40 years in some 80 countries, its effect on sexual development in male frogs could be one of many factors in the global decline of amphibians, he added.

The findings come at gay frgogs time when the EPA is re-evaluating allowable levels gay frgogs atrazine in drinking water, which stand today at 3 parts per billion ppband has drafted new criteria for the protection of aquatic life, limiting four-day average exposures to 12 ppb.

Hayes found hermaphroditism in frogs at levels as low as 0. Even with today's limits, levels of 40 ppb atrazine have been measured in rain and spring water in parts of the Midwest, while atrazine in agricultural runoff can be present at several parts per million. The herbicide also contaminates drinking water supplies in many communities in the Midwest, leading some environmental groups to voice concern about its effect on children, gay frgogs and the fetus.

France, Germany, Italy, Sweden and Norway are among countries that have banned the use of atrazine. The changes he found in the gonads were not discovered with the traditional high-dose atrazine experiments used in the past. In addition, microscopic examination of the internal organs of the frogs is required to detect the hidden effects from low-dose exposure.

To date, atrazine's effects on mammals and amphibians have been tested only at large doses, not at doses commonly found in the environment. In their journal article, Hayes and his colleagues write, "The effective doses in the current study Hayes doubts that atrazine has such severe effects on humans, because the herbicide does not accumulate in tissue and humans don't spend their lives in water like frogs do.

Nevertheless, the effects of atrazine on frogs could be a sign that the herbicide is subtly affecting human sex hormones, too, interfering with androgens, such as testosterone, that control male sex characteristics. Some studies in cell culture point to a possible biochemical explanation for the observed effects on amphibian sex organs.

John P. Giesy, a professor of zoology at Michigan State University in East Lansing, and his colleagues found last year that, at large doses, atrazine ups production of the enzyme aromatase, which converts androgen hormones to estrogen hormones. Extrapolating these results from mammalian cells to amphibians, Hayes argues that atrazine could feminize male frogs by promoting the conversion of male hormones to female hormones.

The lowered androgens would interfere with voice box development, while increased estrogens would promote ovaries within the testes. More than 60 million pounds of the herbicide were applied last year in the United States alone. Manufacturer Syngenta estimates that farmers use the herbicide to control weeds on about two-thirds of all U.

On average, it improves corn yield by slightly more than four percent. The compound is generally considered safe, however, because it quickly decomposes in the environment and, being water soluble, is quickly excreted from the body. Aquatic life, however, swim and breed in atrazine-contaminated field runoff.