Cytochrome P450 induction in mallard duck (MD), black-crowned night heron (BCNH) and Fisher-344 rat

P450 induction was studied in adult and pipping MDs, pipping BCNHs, and rats. Adult MDs and rats received i.p. injection of corn oil, 3-methylcholanthrene (MC) in corn oil (20 mg/kg), saline or phenobarbital (PB) in saline (80 mg/kg) for 3 days. MD and BCNH embryos received MC and PB by injection into the aircell approximately 2 days before pipping and were sacrificed at pipping. Hepatic microsomes were assayed for protein, arylhydrocarbon hydroxylase (AHH), benzphetamine-N-demethylase (BEND), ethoxy-resorufin-O-dealkylase (EROD), pentoxyresorufin-O-dealkylase (PROD), benzyloxyresorufin-O-dealkylase (BROD), ethoxycoumarin-O-dealkylase (ECOD), and by SDS-PAGE with western blot using a polyclonal anti-P4S0IIB antibody and a monoclonal anti-P450IA antibody (MAb 1-12-3). Although species and age caused substantial differences in responses, all treated groups showed an increase in one or more monooxygenase assays. All animals treated with MC showed a strong induction of a protein recognized by anti-P450IA, and all those treated with PB showed strong induction of a band recognized by anti-P450IIB.