In vivo comparison of xenoestrogens using rainbow trout vitellogenin induction as a screening system

Vitellogenin induction in rainbow trout after intraperitoneal injection of test compounds was investigated. Vitellogenin quantification was performed by a direct sandwich enzyme‐linked immunosorbant assay (ELISA) based on polyclonal, affinity purified antibodies. The system was used as a short‐term in vivo screen for estrogenicity and as a tool for establishing the priority of compounds to be tested by water exposure of fish. Representatives from the group of xenoestrogens, bisphenols, phthalates, and pesticides were tested. The relative potency order bisphenol A > bisphenol A dimethacrylate, o,p′‐DDT > butylbenzylphthalate was established, while no significant vitellogenin response was seen with dibutylphthalate, tetrabromobisphenol A, and methoxychlor. Of these, tetrabromobisphenol A has not previously been tested for estrogenicity in vivo. Earlier findings of diminished estrogenic activity of ortho‐substituted compounds was extended to bisphenols since ortho‐bromination of bisphenol A abolished the activity of the parent molecule.