title: [Inhibition of microsomal enzyme activity of the liver by various H2 receptor antagonists].
abstract: The inhibition of 7-ethoxycoumarin deethylase activity by four different H2-receptor antagonists was studied using rat liver microsomes. The compounds tested represent two classes of H2-antagonists, i. e. structures with (cimetidine and oxmetidine) and without (ranitidine and SKF 93479) an imidazole ring. The microsomes were prepared from untreated and phenobarbital-treated animals. It was found that all four compounds, even those without an imidazole ring, inhibited deethylase activity. The compounds inhibited in the following order: SKF 93479 (90%) greater than cimetidine (58%) = oxmetidine (58%) greater than ranitidine (23%). In microsomes from phenobarbital-induced animals, the inhibitory activity of oxmetidine was increased 5-fold. Only the inhibitory potency of cimetidine was increased by preincubation of the H2-antagonist with the microsomes prior to the addition of the substrate.
mesh_terms: D015660:7-Alkoxycoumarin O-Dealkylase; D000818:Animals; D002927:Cimetidine / Q000494:pharmacology; D046508:Culture Techniques; D006635:Histamine H2 Antagonists / Q000494:pharmacology*; D007093:Imidazoles / Q000494:pharmacology; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects*; D010105:Oxygenases / Q000037:antagonists & inhibitors*; D011744:Pyrimidinones / Q000494:pharmacology; D011899:Ranitidine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013329:Structure-Activity Relationship
chemical_list: D006635:Histamine H2 Antagonists; D007093:Imidazoles; D011744:Pyrimidinones; C033275:SK&F 93479; D002927:Cimetidine; D011899:Ranitidine; D010105:Oxygenases; D015660:7-Alkoxycoumarin O-Dealkylase; C027703:oxmetidine
vernacular_title: Hemmung der mikrosomalen Enzymaktivität der Leber durch unterschiedliche H2-Rezeptorantagonisten.