Induction of cytochrome P-448 iso-enzymes and related glucuronyltransferases in the human liver by cigarette smoking

Abstract
Human liver 10–20 mg from biopsy samples removed for diagnostic purposes from selected patients has been used for the preparation of microsomes. The activity of certain mono-oxygenases and UDP-glucuronyltransferases, as well as certain other enzymes involved in drug metabolism, has been determined using different substates as indicators. Smokers oxidized benzo(a)pyrene and 7-ethoxyresorufin and also conjugatedα-naphthol at a significantly increased rate compared to non-smokers. This indicates induction of certain mono-oxygenases and glucuronyltransferases which differs from the induction produced by phenobarbital. The findings can account for the reduced activity and increased elimination rate of certain drugs prescribed to smokers.