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Pure Appl. Chem., Vol. 70, No. 9, pp. 1747-1758, 1998
Natural and anthropogenic environmental
Metabolism and fate of xeno-oestrogens in man
J.G. Liehr 1*, A. Somasunderam 1, and D. Roy 2
*Stehlin Foundation for Cancer Research, 1918
Chenevert Houston, TX 77003, USA.
Abstract: A large variety of chemicals of either natural or synthetic origin possess estrogen-like activity and are thus called xenoestrogens. Some of these chemicals such as the pesticide methoxychlor require metabolic activation for their estrogenic activity, whereas other compounds may themselves be estrogenic and may be deactivated by their metabolism. In this chapter, the metabolism of representative examples of environmental estrogen-like chemicals has been discussed to illustrate common trends in the large structural variety of xenoestrogens. The compounds included are zearalenone, methoxychlor, bisphenol A, DDT, b-sitosterol, and genistein and have been selected based on availaility of information, the potential of exposure of humans and wildlife to the compounds, their industrial or agricultural importance, and the importance of metabolism for their activation or deactivation. The estrogenic activity of phenolic xenoestrogens, a large class of compounds of natural or synthetic origin or their metabolites, likely is based on the weak estrogen receptor binding of phenol. These compounds are mainly metabolized by analogy to steroidal estrogenic hormones, i.e., by aromatic ring hydroxylation (catechol formation), subsequent methylation of the catechol and further phase II metabolism by glucuronide and/or sulfate formation. In contrast, the chlorinated hydrocarbon pesticides, which are weakly estrogenic, are mainly metabolized by dehalogenation at relatively low metabolic rates. Thus, these compounds may persist in the body, accumulate in fatty tissues and provide a chronic reservoir of estrogenic chemicals.
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