ECOESTROGENS AND EMBRYOS - IS THERE A SCIENTIFIC BASIS FOR CONCERN

A variety of estrogenic compounds exist in the environment, both natur al (phyto- and fungal estrogens) and synthetic (e,g. pesticides, indus trial contaminants), Recent studies have suggested that a number of re productive abnormalities in wildlife and human populations could be du e to embryonic exposure to ecoestrogens. These abnormalities include m odifications in gonadal structure and functioning, abnormalities in ge nital morphology and size, depressed plasma sex steroid concentrations and various reproductive organ cancers, We review briefly some of the se studies as well as those providing data that identify various ecoes trogens. The data to date suggest that a wide variety of compounds can interact with the estrogen receptor and can stimulate estrogen-associ ated responses. Compared with 17 beta-estradiol, ecoestrogens have a w eak binding affinity for the estrogen receptor and thus have been desc ribed as weak estrogens, However, we hypothesize that the estrogenic a ction of these compounds is augmented by their bioavailability and per sistence, Initial testing demonstrates that some ecoestrogens show rel atively little affinity for plasma binding proteins; thus, the majorit y of the estrogenic compound in the plasma is available for translocat ion into the cell, Likewise, many synthetic ecoestrogens appear to per sist for months or years, stored in body fat. Future research needs to examine in more detail the relative roles of receptor affinity, cellu lar availability, and nuclear persistence in determining the estrogeni city of ecoestrogens. Only then, will we begin to understand the true role of these compounds in ecosystems.