| Evaluating the Effects of Endocrine Disruptors on Endocrine Function during Development Robert Bigsby,1 Robert E. Chapin,2 George P. Daston,3 Barbara J. Davis,2 Jack Gorski,4 L. Earl Gray,5 Kembra L. Howdeshell,6 R. Thomas Zoeller,7 and Frederick S. vom Saal6 1Indiana University School of Medicine, Indianapolis, Indiana USA;
2National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina USA;
3Procter & Gamble Company, Cincinnati, Ohio USA;
4University of Wisconsin, Madison, Wisconsin USA;
5U.S. Environmental Protection Agency, Research Triangle Park, North Carolina USA;
6University of Missouri, Columbia, Missouri USA;
7University of Massachusetts, Amherst, Massachusetts USA Abstract
The major concerns with endocrine disruptors in the environment are based mostly on effects that have been observed on the developing embryo and fetus. The focus of the present manuscript is on disruption of three hormonal systems: estrogens, androgens, and thyroid hormones. These three hormonal systems have been well characterized with regard to their roles in normal development, and their actions during development are known to be perturbed by endocrine-disrupting chemicals. During development, organs are especially sensitive to low concentrations of the sex steroids and thyroid hormones. Changes induced by exposure to these hormones during development are often irreversible, in contrast with the reversible changes induced by transient hormone exposure in the adult. Although it is known that there are differences in embryonic/fetal/neonatal versus adult endocrine responses, minimal experimental information is available to aid in characterizing the risk of endocrine disruptors with regard to a number of issues. Issues discussed here include the hypothesis of greater sensitivity of embryos/fetuses to endocrine disruptors, irreversible consequences of exposure before maturation of homeostatic systems and during periods of genetic imprinting, and quantitative information related to the shape of the dose-response curve for specific developmental phenomena. Key words: androgen, development, embryo, endocrine disruptors, estrogens, fetus, thyroid. -- Environ Health Perspect 107(suppl 4) :613-618 (1999) . http://ehpnet1.niehs.nih.gov/docs/1999/suppl-4/613-618bigsby/abstract.html
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