In vivo effects of 3-methylcholanthrene, phenobarbital, pyrethrum and 2,4,5-T isooctylester on liver, lung and kidney microsomal mixed-function oxidase system of guinea-pig: a comparative study.
The optimum conditions (pH, microsomal protein amount and substrate concentration) of guinea-pig liver, lung and kidney microsomal aniline 4-hydroxylase, ethylmorphine N-demethylase and benzo[a]pyrene hydroxylase activities were determined. Male guinea-pigs weighing 500-700 g were administered 3-methylcholanthrene (25 mg/kg, i.p. 3 days), phenobarbital (75 mg/kg, i.p. 3 days), pyrethrum (120 mg/kg, i.p. 2 days) and 2,4,5-T isooctylester (200 mg/kg, i.p. 3 days). 3-Methylcholanthrene treatment caused significant increases in liver microsomal benzo[a]pyrene hydroxylase and kidney microsomal aniline 4-hydroxylase activities. However, with phenobarbital treatment the only significant increase was observed in liver microsomal ethylmorphine N-demethylase activity. Pyrethrum treatment decreased kidney microsomal ethylmorphine N-demethylase activity significantly. 2,4,5-T isooctylester treatment increased liver microsomal aniline 4-hydroxylase and lung microsomal ethylmorphine N-demethylase activities significantly. Liver microsomal NADPH-cytochrome c reductase activity was increased significantly by phenobarbital and pyrethrum treatment. The other treatments did not cause any significant changes in microsomal NADPH-cytochrome c reductase activities of liver, lung and kidney. Cytochrome P-450 content of guinea-pig liver microsomes were increased significantly about 2.5-fold and 2-fold by treatment with 3-methylcholanthrene and phenobarbital, respectively. 3-Methylcholanthrene also caused 1 nm spectral shift in the absorption maxima of CO difference spectrum of the dithionite-reduced liver microsomal cytochrome P-450, forming P-449.
D015085:2,4,5-Trichlorophenoxyacetic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D000815:Aniline Hydroxylase / Q000378:metabolism; D000818:Animals; D001579:Benzopyrene Hydroxylase / Q000378:metabolism; D011723:Chrysanthemum cinerariifolium; D005037:Ethylmorphine-N-Demethylase / Q000378:metabolism; D006168:Guinea Pigs; D007668:Kidney / Q000187:drug effects* / Q000201:enzymology; D008099:Liver / Q000187:drug effects* / Q000201:enzymology; D008168:Lung / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D008748:Methylcholanthrene / Q000494:pharmacology*; D008861:Microsomes / Q000201:enzymology; D008862:Microsomes, Liver / Q000201:enzymology; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D010634:Phenobarbital / Q000494:pharmacology*
C040460:2,4,5-T isooctyl ester; D008748:Methylcholanthrene; D015085:2,4,5-Trichlorophenoxyacetic Acid; D006899:Mixed Function Oxygenases; D000815:Aniline Hydroxylase; D001579:Benzopyrene Hydroxylase; D005037:Ethylmorphine-N-Demethylase; D010634:Phenobarbital