title: Effects of superoxide dismutase on cholesterol 7 alpha-hydroxylation in swine.
abstract: Effects of carbon monoxide, nitrogen, ferricytochrome c and p-hydroxymercuribenzoate were studied on cholesterol 7 alpha-hydroxylase activity of swine hepatic microsomes. The results suggest that a microsomal electron transport system is involved in hepatic microsomal cholesterol 7 alpha-hydroxylation in swine. Cholesterol 7 alpha-hydroxylation is inhibited by superoxide dismutase in the standard assay system containing a NADPH generating system. Superoxide dismutase also inhibited cholesterol 7 alpha-hydroxylation in the system where superoxides were generated by enzymatic or nonenzymatic means in the absence of NADPH-generating system. The current study suggests that superoxide anion may be an important factor in the cholesterol 7 alpha-hydroxylation of swine.
mesh_terms: D000818:Animals; D002248:Carbon Monoxide / Q000494:pharmacology; D002790:Cholesterol 7-alpha-Hydroxylase / Q000037:antagonists & inhibitors*; D003574:Cytochrome c Group / Q000494:pharmacology; D006902:Hydroxymercuribenzoates / Q000494:pharmacology; D000860:Hypoxia; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D013250:Steroid Hydroxylases / Q000037:antagonists & inhibitors*; D013482:Superoxide Dismutase / Q000494:pharmacology*; D013552:Swine
chemical_list: D003574:Cytochrome c Group; D006902:Hydroxymercuribenzoates; D002248:Carbon Monoxide; D013250:Steroid Hydroxylases; D002790:Cholesterol 7-alpha-Hydroxylase; D013482:Superoxide Dismutase