Androgen concentration and partial characterization of 5alpha reductase in the epididymis of the rhesus monkey.
The 5alpha reductase activity ofthe monkey epididymis was studied. The enzyme was found in particulate subcellular fractions, its distribution closely resembling that of the microsomal marker enzyme NADPH: cytochrome c reductase, suggesting an association of 5alpha reductase with membranes of the endoplasmic reticulum. Maximal enzyme activity was found at pH 5.4 and at 32--37 C. The crude nuclear preparation had a Km: 0.315 x 10(-6)M and Vmax: 168 pmoles/mg protein/h. The microsomal enzyme had a Km: 0.243 x 10(-6)M and Vmax: 828 pmoles/mg protein/h. Neither enzyme preparation was affected by addition to the incubation media of dihydrotestosterone (DHT) or 5alpha-androstane-3alpha,17beta-diol. The endogenous androgen concentration in the epididymides of 2 different monkeys, in ng/g wet weight was: DHT 20.81 +/- 1.98; T: 9.0L +/- 2.83; diol: 3.03 +/- 0.41.
D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000378:metabolism*; D000728:Androgens / Q000378:metabolism*; D000818:Animals; D004822:Epididymis / Q000378:metabolism*; D000882:Haplorhini; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008253:Macaca mulatta; D008297:Male; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism*; D013347:Subcellular Fractions / Q000201:enzymology
D000728:Androgens; D010088:Oxidoreductases; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase; D009251:NADPH-Ferrihemoprotein Reductase