Uranium, the newest 'hormone'.The incidence of several cancers is especially high on the Four Corners Navajo Reservation, which straddles the Arizona-New Mexico border. Because the region hosts more than 2,000 abandoned uranium mines Uranium mining is presently carried out in more than 25 countries around the world. An estimated 100 or more uranium mines in different stages of development are reported. Major uranium mines are located in Canada, Australia and Kazakhstan that contribute more than half of world's uranium , many of which release dust into the air and water, area researchers wondered whether mine pollution might partially explain the high rate of reproductive-organ cancers in teenage Navajo girls--a rate 17 times that of U.S. girls generally. New animal studies led by Cheryl A. Dyer and Stefanie R. Whish of Northern Arizona University Northern Arizona University (NAU) is a public university in Flagstaff, Arizona in the United States. As of Fall 2007, the university has 21,352 students, 13,989 of these are situated in the main Flagstaff campus<ref name="Enrollment" />. in Flagstaff Flagstaff, city (1990 pop. 45,857), seat of Coconino co., N Ariz., near the San Francisco Peaks; inc. 1894. Lumbering, ranching, and a lively tourist trade thrive in the region, where many ruined pueblos, numerous state parks, several lakes, and large pine forests support that suspicion. The researchers exposed young female mice to a soluble form of uranium similar to what enters groundwater from mines. To limit the animals' production of natural estrogens Estrogens Hormones produced by the ovaries, the female sex glands. Mentioned in: Acne, Polycystic Ovary Syndrome estrogens (es´trōjenz), n. , the researchers removed the ovaries--the hormones' main source--from all the mice in the study. Estrogens are known to be a leading cause of many reproductive cancers. For 1 month, most mice received drinking water drinking water supply of water available to animals for drinking supplied via nipples, in troughs, dams, ponds and larger natural water sources; an insufficient supply leads to dehydration; it can be the source of infection, e.g. leptospirosis, salmonellosis, or of poisoning, e.g. laced with uranium or diethylstilbestrol diethylstilbestrol: see DES. (DES), an estrogen-mimicking drug. Concentrations of the uranium were half the amount that the Environmental Protection Agency Environmental Protection Agency (EPA), independent agency of the U.S. government, with headquarters in Washington, D.C. It was established in 1970 to reduce and control air and water pollution, noise pollution, and radiation and to ensure the safe handling and permits in drinking water and roughly one-tenth the concentration found in some water wells on the reservation. Mice getting DES- or uranium-treated water showed classic markers of heavy estrogen exposure, but mice receiving plain water didn't, Whish notes. In animals drinking the spiked water, for instance, the external opening of the vagina developed early, cells lining the vagina were bigger than normal and exhibited protein changes akin to those that produce nails and corns, and the uterus weighed significantly more than normal. In related test-tube experiments, uranium exposure increased the proliferation of breast-cancer cells, just as estrogen does. None of these changes accompanied uranium exposure if the animals also received injections of a chemical that blocks estrogen's access to cells. This evidence strongly suggests that "uranium is acting as an estrogen," says Whish. --J.R. |
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