Developmental neurotoxicity of endocrine disrupters: focus on estrogens

A number of different environmental compounds are proposed to interact with the endocrine system (i.e., endocrine disrupters). Many of these have estrogenic effects in vitro and/or in vivo. Recent reviews have focused attention on the need for assessing the neurotoxicity of these compounds following developmental exposure. This attention comes in part from the literature on the effects of developmental exposure to exogenous estrogen on later behavioral and neuropathological alterations. A review of the ongoing neurobehavioral and neuropathological studies at the National Center for Toxicological Research on four such estrogen mimics (genistein, methoxychlor, nonylphenol, and ethinyl estradiol) is presented with results indicating that intake of a sodium solution is sensitive to these estrogen mimics. Developmental dietary exposure in male and female rats resulted in increased consumption of the sodium solution. Volume of the sexually dimorphic nucleus of the medial preoptic area was reduced by genistein, nonylphenol, and ethinyl estradiol exposure in males. The regulatory impact of these data and the directions for future research are discussed.