ABSTRACT
Xenobiotics of widely diverse chemical structures have estrogenic properties. This diversity makes it difficult to predict the estrogenicity of chemicals solely on a structural basis. Hence, their identification as estrogens has relied on bioassays using diverse end points on which estrogens play a direct or indirect role. Humans and wildlife are exposed to a variety of chemicals simultaneously. Residues of diverse estrogenic xenobiotics coexist in the fat and body fluids of exposed individuals. Thus, it is likely that they may become bioavailable, for example, during fasting or nursing. Novel xenoestrogens have been found among antioxidants, plasticizers, PCB congeners, disinfectants, pesticides, and sunscreens. The newly identified estrogens not only induce cell proliferation but also increase the expression of pS2 and progesterone receptor. Significant progress has been made in establishing that perinatal exposure to low, environmentally relevant doses of xenoestrogens induces morphological and functional alterations in the male and female genital tract and the mammary gland.
