Introduction

Evidence is accumulating that many common environmental toxicants are capable of disrupting developmental processes by interfering with the actions of endogenous hormones. Public attention has focused on apparent increases in hormone dependent cancers of both male and female reproductive organs, which cannot be accounted for simply by improvements in detection methods.1,2 In wildlife species, an array of abnormal physiological and morphological responses likely to compromise reproductive fitness has been noted. Hormonal disturbances in wildlife include sex changes in riverine fish and marine snails, reproductive failure in birds and abnormalities in the reproductive organs of alligators and polar bears. The term endocrine disruption has been used to describe a range of such effects that may be acting through entirely different mechanisms. For the purpose of this review, the term endocrine disruptor is defined as any exogenous agent that causes adverse health effects in an intact organism, or its progeny, consequent to changes in endocrine function.3 Endocrine disruptors may act to (1) mimic the effects of hormones, (2) antagonise the effects of hormones, (3) alter the pattern of synthesis and metabolism of hormones and (4) modify hormone receptor levels.4 The most widely studied of these effects to date is the action of diverse substances which mimic the action of endogenous estrogen, either through interaction with the estrogen receptor, or through other mechanisms. These are referred to as estrogenic xenobiotics, exoestrogens or xenoestrogens. In this article, the effects of endocrine disrupting chemicals in a range of

1 R.M. Sharpe and N.E. Skakkebaek, Lancet, 1993, 341, 1392-5.

2 T. Colborn, J. Peterson Myers and D. Dumanoski, Our Stolen Future, Little, Brown, Boston, 1996.

3 P. Grandjean et al, presented at the European Workshop on the Impact of Endocrine Disruptors on Human Health and Wildlife, Weybridge, UK, 1996, Environment and Climate Research Programme, DGXII, European Commission Publication EUR 17549, p. 5.

4 A. M. Soto, C. Sonnenschien, K. L. Chung, M. F. Fernandez, N. Olea and F. O. Serrano, Environ. Health Perspect., 1995, 103 (suppl.), 113.

Issues in Environmental Science and Technology No. 12

Endocrine Disrupting Chemicals © The Royal Society of Chemistry, 1999

invertebrate species are considered and the potential ecological significance discussed.

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