title: Nicotinamide-induced hepatic microsomal mixed function oxidase system in rats.
abstract: A single intraperitoneal injection of nicotinamide (100 mg/kg body wt.), an endogenous non-toxic metabolite, to male rats was shown to significantly induce all the components of the hepatic microsomal mixed function oxidase system such as NADPH-cytochrome c reductase, cytochrome P-450 and cytochrome b5 as well as activities of drug-metabolizing enzymes such as arylhydrocarbon hydroxylase, aminopyrine demethylase and UDPglucuronosyltransferase. Tryptophan (1000 mg/kg body wt.) and nicotinic acid (200 mg/kg body wt.) as well as methionine (20 mg/kg body wt.) were also shown to be effective inducers in terms of hepatic NADPH-cytochrome c reductase activity. The nicotinamide-induced mixed function oxidase system was shown to be associated with an increased incorporation of 14C-labelled leucine into hepatic microsomal proteins which was inhibited by puromycin. Nicotinamide was shown to induce a distinct pattern of drug-metabolizing system in comparison with that of phenobarbital.
mesh_terms: D000633:Aminopyrine N-Demethylase / Q000378:metabolism; D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism; D003580:Cytochromes / Q000378:metabolism; D005260:Female; D014453:Glucuronosyltransferase / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008715:Methionine / Q000494:pharmacology; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism; D009536:Niacinamide / Q000494:pharmacology*; D010088:Oxidoreductases / Q000378:metabolism*; D011691:Puromycin / Q000494:pharmacology; D051381:Rats; D014364:Tryptophan / Q000494:pharmacology
chemical_list: D003580:Cytochromes; D009536:Niacinamide; D011691:Puromycin; D014364:Tryptophan; D008715:Methionine; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; D001189:Aryl Hydrocarbon Hydroxylases; D000633:Aminopyrine N-Demethylase; D009251:NADPH-Ferrihemoprotein Reductase; D014453:Glucuronosyltransferase