Chemical-Induced Estrogenicity

Estrogens are critical hormones required for human health, but they have also been linked to human diseases. Inappropriate exposures to estrogens during critical developmental periods or later in life can lead to adverse health effects and these considerations have been important for the scientific, regulatory, and public concern regarding exposures of wildlife and humans to endocrine disrupting compounds and particularly those that exhibit estrogenic activity. An increasing number of industrial products or byproducts exhibit estrogenic activity and these include organochlorine pesticides, some polychlorinated biphenyls (PCBs), and phenolic compounds, such as alkylphenols and bisphenol A (BPA). Many of the estrogenic endocrine disruptors of concern including BPA have multiple activities, and this raises problems for risk assessment of these compounds. Moreover, mechanistic studies demonstrate that estrogenic endocrine disruptors are selective estrogen receptor (ER) modulators and exhibit tissue-specific ER agonist/antagonist activities that can only be determined by extensive research and not by simple predictive receptor binding or transactivation studies in cell culture models.