title: NADPH-cytochrome P-450 reductase is not a component of the liver microsomal steroid 5-alpha reductase.
abstract: Liver microsomal steroid 5-alpha-reduction is catalyzed by a NADPH-dependent enzyme system. The requirement of NADPH-cytochrome P-450 reductase to shuttle reduction equivalents from NADPH to steroid 5-alpha-reductase was investigated using an inhibitory antibody against NADPH-cytochrome P-450 reductase. This antibody preparation inhibited cytochrome c reduction in microsomes from female rat liver with an I50 of 0.75 mg antibody/mg of microsomal protein. Benzphetamine N-demethylation and testosterone 6-beta-hydroxylation, two cytochrome P-450-mediated oxidative reactions, were inhibited by the antibody. On the other hand, testosterone 5-alpha-reductase was not affected by the antibody. These results suggest that NADPH-cytochrome P-450 reductase is not an obligatory component of the liver microsomal steroid 5-alpha-reduction.
authors.affiliation: Dept. Pediatrics, Cornell University Medical College, NY, NY 10021.
authors.forename: K C
authors.initials: KC
authors.lastname: Cheng
authors.forename: R W
authors.initials: RW
authors.lastname: Wang
authors.forename: A Y
authors.initials: AY
authors.lastname: Lu
mesh_terms: D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D000818:Animals; D000906:Antibodies; D000936:Antigen-Antibody Complex; D005260:Female; D007700:Kinetics; D008862:Microsomes, Liver / Q000201:enzymology*; D009251:NADPH-Ferrihemoprotein Reductase / Q000032:analysis* / Q000276:immunology; D051381:Rats
chemical_list: D000906:Antibodies; D000936:Antigen-Antibody Complex; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase; D009251:NADPH-Ferrihemoprotein Reductase