Breast effects of hormonal pollutants.Breast tissue is exquisitely sensitive to its hormonal milieu, especially the body's rhythmic ebbs and flows of estrogen and other sex hormones. Might the developing ubiquity of pollutants that mimic these hormones (SN: 1/8/94, p.24) be affecting breast cancer rates in women (SN: 7/3/93, p.10)? That question spurred Nadine M. Brown and Coral A. Lamartiniere of the University of Alabama at Birmingham UAB began in 1936 as the Birmingham Extension Center of the University of Alabama. Because of the rapid growth of the Birmingham area, it was decided that an extension program for students who had difficulties which prevented them from studying in Tuscaloosa was needed. to study such agents in female rats approaching puberty. In the July-August Environmental Health Perspectives, they report that these compounds indeed alter the maturation rate of mammary mammary /mam·ma·ry/ (mam´ah-re) pertaining to the mammary gland, or breast. mam·ma·ry adj. Of or relating to a breast or mamma. mammary pertaining to the mammary gland. tissue, which can change vulnerability to cancer. Breast tissue begins its gradual maturation early in a rodent's life. As in humans, immature breast tissue in rats consists of bulb-shaped terminal end buds that, under the direction of female sex hormones, branch out and differentiate into a tree of lobules Lobules A small lobe or subdivision of a lobe (often on a gland) that may be seen on the surface of the gland by bumps or bulges. Mentioned in: Fibrocystic Condition of the Breast . These lobules, which secrete milk when stimulated by the hormonal changes of pregnancy, face a far lower risk than end buds of turning cancerous. So the researchers assayed end-bud-to-lobule transformation rates following week-long exposures to hormonelike chemicals. Compared to untreated rats, those given DDT DDT or 2,2-bis(p-chlorophenyl)-1,1,1,-trichloroethane, chlorinated hydrocarbon compound used as an insecticide. First introduced during the 1940s, it killed insects that spread disease and feed on crops. , the drug diethylstilbestrol diethylstilbestrol: see DES. (a synthetic estrogen), or genistein (a plant estrogen found in soybeans) all exhibited a host of mammary changes characterized by cellular proliferation, a decreased proportion of end buds, and an increased share of lobules. By hastening mammary development, these changes might be interpreted as reducing the tissue's window of vulnerability A window of vulnerability or wov is a time frame within which defensive measures are reduced, compromised or lacking. The term is used with reference to military defences of strategic assets, and also by analogy in computer software to a software vulnerability which is open to carcinogens Carcinogens Substances in the environment that cause cancer, presumably by inducing mutations, with prolonged exposure. Mentioned in: Colon Cancer, Rectal Cancer , Brown says. Indeed, she points out, the genistein data may explain why women in Japan--with its soy-rich cuisines--face such a low incidence of breast cancer. By contrast, TCDD--the most potent dioxin--retarded mammary maturation. Says Brown, this "potentially detrimental" change certainly raises a question about whether TCDD might indirectly contribute to cancer risk by lengthening the window of vulnerability to breast carcinogens. |
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