title: Initial characterization of drug-metabolizing systems in the liver of the Northern pike, Esox lucius.
abstract: NADPH-cytochrome c reductase, cytochrome -450, benzo[a]pyrene mono-oxygenase, epoxide hydratase, and glutathione S-transferase activities in the liver of the Northern pike (Esox lucius) have been measured and partially characterized. The level of these systems in pike liver is between 13.2 and 133% of the corresponding levels in rat liver, with the exception of glutathione S-transferase, whose specific activity in the high-speed supernatant fraction of pike liver is 305% of that in rat liver. In addition, pike liver contains about 23% of the mammalian level of reduced glutathione. Drug-metabolizing systems in pike liver are distributed in essentially the same manner in subfractions as the corresponding systems in the liver of mammals. Benzo[a]pyrene mono-oxygenase and epoxide hydratase activities display the expected pH maxima of 7.5 and 9.5, respectively, and have temperature maxima of 37 degrees and 47 degrees C, respectively. NADPH-cytochrome c reductase and glutathione S-transferase activities are relatively independent of temperature. Intraperitoneal treatment of Northern pike with methylcholanthrene induces the benzo[a]pyrene mono-oxygenase activity of liver microsomes 33-fold.
mesh_terms: D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism*; D001579:Benzopyrene Hydroxylase / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004790:Enzyme Induction; D004851:Epoxide Hydrolases / Q000378:metabolism*; D005260:Female; D005399:Fishes / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008099:Liver / Q000201:enzymology*; D008297:Male; D008748:Methylcholanthrene / Q000494:pharmacology; D008862:Microsomes, Liver / Q000201:enzymology; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism*; D010634:Phenobarbital / Q000494:pharmacology; D013696:Temperature
chemical_list: D008748:Methylcholanthrene; D003577:Cytochrome P-450 Enzyme System; D001579:Benzopyrene Hydroxylase; D001189:Aryl Hydrocarbon Hydroxylases; D009251:NADPH-Ferrihemoprotein Reductase; D005982:Glutathione Transferase; D004851:Epoxide Hydrolases; D010634:Phenobarbital