title: Effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin and phenobarbital on the occurrence and distribution of four cytochrome P-450 isozymes in rabbit kidney, lung, and liver.
abstract: The effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and of phenobarbital (PB) on the distribution and occurrence of four cytochrome P-450 isozymes, Forms 2, 3, 4, and 6, in the kidney, lung, and liver of adult male rabbits was investigated using immunofluorescence. In the kidney, Forms 2 and 3 were localized in the proximal tubules of both untreated and PB-treated animals, while antibodies to Forms 4 and 6 showed weak to negative staining. In TCDD-pretreated animals, Forms 4 and 6 appeared in the renal endothelium, in addition to staining the proximal tubular epithelium intensely. Form 2 was the only isoenzyme of those studied found to be present in the lungs of normal and PB-pretreated rabbits; it was also present in lungs of TCDD-pretreated rabbits. Form 3 was not detected in any of the rabbit lungs examined. Forms 4 and 6, while not apparent in the lungs of normal or PB-treated animals, were found in the lungs of TCDD-treated animals and also appeared in the endothelium of the pulmonary arteries and veins. All forms tested were present in control liver. The staining for Form 2 was intense in the livers of PB-pretreated animals, as was the staining for Forms 4 and 6 in the livers of TCDD-pretreated animals. Our results indicate that, while PB altered the intensity of staining for Form 2 in the liver and kidney, TCDD altered both the staining intensity and distribution of the isozymes in kidney, lung, and liver, producing, for example, a localization of Forms 4 and 6 in the endothelium of both the kidney and lung which was not seen in either untreated or PB-pretreated rabbits.
mesh_terms: D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000032:analysis*; D004147:Dioxins / Q000494:pharmacology*; D004790:Enzyme Induction; D005455:Fluorescent Antibody Technique; D007527:Isoenzymes / Q000032:analysis*; D007668:Kidney / Q000201:enzymology*; D008099:Liver / Q000201:enzymology*; D008168:Lung / Q000201:enzymology*; D008297:Male; D008748:Methylcholanthrene / Q000494:pharmacology; D010634:Phenobarbital / Q000494:pharmacology*; D000072317:Polychlorinated Dibenzodioxins / Q000494:pharmacology*; D011817:Rabbits
chemical_list: D004147:Dioxins; D007527:Isoenzymes; D000072317:Polychlorinated Dibenzodioxins; D008748:Methylcholanthrene; D003577:Cytochrome P-450 Enzyme System; D010634:Phenobarbital