The oxidation of isomeric amino and acetamidobiphenyls by rat hepatic microsomal preparations.

The metabolism of isomeric amino and acetamidobiphenyls was studied using rat liver microsomal preparations. The aromatic amines were hydroxylated ortho or para to the amino group, whereas the aromatic amides were mainly oxidized in the para position. The carcinogenic amines 3- and 4- aminobiphenyl were converted to hydroxylamines and nitroso compounds. The non-carcinogenic amine 2-aminobiphenyl was resistant to enzymic nitrogen oxidation. The results support the concept that oxidation of aromatic amino groups is a prerequisite for carcinogenic and mutagenic activity.