Enzymic and electrophoretic characterization of the hexachlorobenzene-induced cytochrome P-450 in the liver of rat.

1. Hexachlorobenzene induces the cytochtome P-450 system in rat liver microsomes. The catalytic activity of the enzyme towards various substrates (dealkylation of 7-ethoxycoumarin, hydroxylation of biphenyl and NADPH-dependent reduction of cytochrome c) corresponds to that obtained in animals treated with a mixture of phenobarbital and benzpyrene. 2. Electrophoretic separation of the partly purified hexachlorobenzene-induced cytochrome P-450 in sodium dodecyl sulphate polyacrylamide gels exhibits a protein pattern similar to that found in microsomes from rats treated with phenobarbital plus benzpyrene.