In vitro androgen metabolism in mouse kidney: High 3-keto-reductase (3α-hydroxysteroid dehydrogenase) activity relative to 5α-reductase

摘要: Abstract The in vitro metabolism of testosterone and dihydrotestosterone was studied slices cell fractions mouse kidney. When used as substrate, very little to occurred suggesting low 5α-reductase activity. it rapidly converted 5α-androstane-3α, 17β-diol by a potent 3-keto-reductase. Ninety-five percent this latter enzyme is located cytosol requires NADPH cofactor. 3-keto-reductase may exist two molecular forms which can be separated polyacrylamide gel electrophoresis. Form A B have mean radii correspond weights 38, 700 28, 700, respectively. Sufficient activity present at 0°C reduce physiological concentrations (2×10−9 M) without the addition 3-Keto-reductase higher intact male than castrate or female mice increases with androgen treatment. From these studies we conclude: (a) virtual absence kidney consistent thesis that rather intracellular organ. (b) Kinetic depend upon uptake retention receptor proteins difficult interpret due rapid ligand.