Phenone, Hydroxybenzophenone, and Branched Phenone Estrogen Receptor Binding and Vitellogenin Agonism in Rainbow Trout in Vitro Models

Phenones and hydroxy benzophenones are widely used as UV radiation filters, and in the manufacturing of insecticides and pharmaceuticals. Understanding the estrogenic potential these chemicals is of interest to the US Environmental Protection Agency and other international environmental organizations. The current study sequentially combined complementary in vitro rainbow trout estrogen receptor (rtER) binding and liver slice vitellogenin (Vtg) mRNA induction assays in the context of a defined ER-mediated adverse outcome pathway (AOP). Cyclic phenones, branched phenones, and hydroxybenzophenones bound to rtER with relative potency ranging from no affinity to high binding affinity of 0.11%, and many induced Vtg gene expression in rt liver slices. In addition, cyclohexylphenylketone which did not bind rtER binding in cytosol was biotransformed within liver tissue to a chemical that induced Vtg expression.