title: Investigation of the type of induction of microsomal monooxygenases by polycyclic hydrocarbons.
abstract: The severity of the induced effect of the polycyclic hydrocarbon 3-methylcholanthrene on monooxygenase of the microsomal fraction of the liver as a function of the number of binding sites for this inducer in the active site of cytochrome P-450 was investigated. In vivo models, in which the primary bounding and metabolism of a polycyclic hydrocarbon in the microsomes is increased or sharply inhibited, are presented. It is concluded that in the mechanism of induction by 3-methylcholanthrene, the activation of synthesis of specific protein (cytochrome P-448) is accomplished not by the initial molecule of the inducer, but by products of its primary metabolism in the microsomes.
mesh_terms: D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000096:biosynthesis*; D001579:Benzopyrene Hydroxylase / Q000096:biosynthesis*; D001665:Binding Sites; D002779:Cholestasis / Q000201:enzymology; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D003580:Cytochromes / Q000378:metabolism*; D004790:Enzyme Induction / Q000187:drug effects; D006498:Hepatectomy; D008297:Male; D008748:Methylcholanthrene / Q000494:pharmacology*; D008862:Microsomes, Liver / Q000201:enzymology*; D010634:Phenobarbital / Q000494:pharmacology; D051381:Rats
chemical_list: D003580:Cytochromes; D008748:Methylcholanthrene; D003577:Cytochrome P-450 Enzyme System; D001579:Benzopyrene Hydroxylase; D001189:Aryl Hydrocarbon Hydroxylases; D010634:Phenobarbital