Mechanisms of action and suspected effects of xenohormones

During the last few years, several chemical compounds that are environmenta l pollutants have been shown to display xenohormonal activity, and have bee n called endocrine disrupters. In particular, several pesticides and herbic ides bind the estrogen receptor and activate oestradiol-dependent gene prom oters. It has been suggested that these compounds could account for the inc rease in both the male reproductive disorders as well as the incidence of t esticular cancer. This hypothesis which remains controversial, is strenghth ened by the well known toxic effects in human and in animals of the drug di ethyl stilbestrol, an estrogen mimetic. Xeno-estrogens could act during fet al life by altering the organogenesis of the reproductive system or by disr upting the gonadotropin-steroid hormones feedback loop. Other xenobiotics c ould act through their anti-androgenic activity Or by modifying the metabol ism or the half-life of the steroid hormones. Since endocrine disrupters co uld prove to be harmful to man and animals, several in vivo or in vitro tes ts have been developped to assay for their functional activity.