Increase of liver microsomal benzo(a)pyrene monooxygenase activity by subsequent glucuronidation.

Benzo(a)pyrene monooxygenase activity in rat and guinea pig liver microsomes is markedly stimulated when UDP-glucuronic acid is present in the assay. This effect is further enhanced by addition of UDP-N-acetylglucosamine, an allosteric activator of UDP-glucuronyltransferase. The results suggest a coupling between microsomal monooxygenase and UDP-glucuronyltransferase which may assist elimination of toxic compounds.