Endocrine disruptors: update on xenoestrogens

Endocrine disrupters and their possible impact on human and animal health h ave become a topic of discussion and an area of active research in toxicolo gy. A focus has been on xenoestrogens, i.e., environmental chemicals with e strogenic activity. In principle, there is agreement that such compounds, i n high doses, may cause developmental, reproductive and tumorigenic effects ("hazard"). A matter of controversy is the question of risks associated wi th xenoestrogens under realistic (low) exposure scenarios; this is due to u ncertainty on how to assess the interactions of exogenous compounds with th e endocrine system and its complex regulation. Our overview will address to pics including: consequences from previous clinical use of the potent estro gen diethylstilbestrol with particular emphasis on dose-response relationsh ips, other observations in humans exposed to estrogenic chemicals in an occ upational context, and available information on exposure levels of syntheti c and naturally occurring estrogens in the diet. Together with a critical a ppraisal of methods to detect and quantitate the estrogenic activity of syn thetic and naturally occurring chemicals, novel aspects in the risk assessm ent for endocrine active compounds are discussed.