Formation of hydroxy radicals by environmental estrogen-like chemicals in rat striatum.

We investigated effects of environmental estrogen-like chemicals, para-nonylphenol and bisphenol A, on hydroxy radical formation in the striatum of adult rats, using an in vivo microdialysis system. Para-nonylphenol significantly stimulated hydroxy radical formation in the striatum. Bisphenol A also increased hydroxy radical formation, albeit effect being slight. The formation of hydroxy radicals induced by para-nonylphenol was dose-dependently inhibited by tamoxifen, which suggests that the effect of this chemical was an estrogenic action via estrogen receptors. The results of the present study are the first demonstration on hydroxy radical formation induced by environmental estrogen-like chemicals and suggest that the in vivo microdialysis may be useful for evaluating toxic effects of environmental chemicals on nervous tissues.