title: Induction of the hepatic microsomal and nuclear cytochrome P-450 system by hexachlorobenzene, pentachlorophenol and trichlorophenol.
abstract: The application of hexachlorobenzene (HCB), pentachlorophenol (PCP) and 2,4,5-trichlorophenol (TCP) to female rats led to an induction of both the microsomal and the nuclear cytochrome P-450 system in the liver. The increase of th mixed-function hydroxylase activities examined (7-ethoxycoumarin deethylase, 7-ethoxyresorufin deethylase, NADPH-dependent cytochrome c reductase, aminopyrine demethylase, benzpyrene hydroxylase) did not correlate strictly with the cytochrome P-450 content. Depending on the inducers and the substrates used, the content and the activity of the cytochrome P-450 were essentially smaller in the nuclei than in the microsomes. It was striking that in the nuclei those activities (benzpyrene hydroxylase, 7-ethoxyresorufin deethylase, 7-ethoxycoumarin deethylase) were preferably induced which can be attributed to the methyl-cholanthrene-induced form of the cytochrome P-450 (cytochrome P-448). These results suggest, also in the light of findings of other authors, the induction of different species of cytochrome P-450 in the nuclei and microsomes.
mesh_terms: D015660:7-Alkoxycoumarin O-Dealkylase; D000818:Animals; D001579:Benzopyrene Hydroxylase / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects* / Q000201:enzymology; D002722:Chlorobenzenes / Q000494:pharmacology*; D002733:Chlorophenols / Q000378:metabolism / Q000494:pharmacology*; D019363:Cytochrome P-450 CYP1A1; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis*; D005260:Female; D006581:Hexachlorobenzene / Q000494:pharmacology*; D008862:Microsomes, Liver / Q000187:drug effects* / Q000201:enzymology; D010078:Oxazines / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D010105:Oxygenases / Q000378:metabolism; D010416:Pentachlorophenol / Q000494:pharmacology*; D051381:Rats
chemical_list: D002722:Chlorobenzenes; D002733:Chlorophenols; D010078:Oxazines; C009534:2,4,5-trichlorophenol; D006581:Hexachlorobenzene; D003577:Cytochrome P-450 Enzyme System; D010416:Pentachlorophenol; D010088:Oxidoreductases; D010105:Oxygenases; D015660:7-Alkoxycoumarin O-Dealkylase; D001579:Benzopyrene Hydroxylase; D019363:Cytochrome P-450 CYP1A1