title: Non-competitive inhibition of hepatic and intestinal aryl hydrocarbon hydroxylase activities from rats by rifampin.
abstract: Rifampin is a semisynthetic antibiotic which is known to alter hepatic cytochrome P-450 mediated drug metabolizing enzymes. Using benzo(a)pyrene as the substrate we have shown that rifampin acts as a non-competitive inhibitor of hepatic microsomal aryl hydrocarbon hydroxylase in vitro at or below 0.10 mM and that it is also a non-competitive inhibitor of intestinal aryl hydrocarbon hydroxylase at or below 0.075 mM. These results suggest that the administration of rifampin with other drugs may result in altered drug biotransformation.
mesh_terms: D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism*; D001580:Benzopyrenes / Q000378:metabolism; D001667:Binding, Competitive / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D007422:Intestines / Q000201:enzymology*; D008099:Liver / Q000201:enzymology*; D008297:Male; D008861:Microsomes / Q000201:enzymology; D008862:Microsomes, Liver / Q000201:enzymology; D051381:Rats; D012293:Rifampin / Q000494:pharmacology*
chemical_list: D001580:Benzopyrenes; D004791:Enzyme Inhibitors; D001189:Aryl Hydrocarbon Hydroxylases; D012293:Rifampin