Determination of delta 5 3 beta-hydroxysteroid dehydrogenase activity in intact isolated rat Leydig cells.
A method for the determination of delta 5 3 beta-hydroxysteroid dehydrogenase-isomerase (3 beta-HSD) activity in intact isolated Leydig cells was established. This method utilizes the conversion of [7-3H]dehydroepiandrosterone (1.04 mumole) to androstenedione and expresses the activity of the enzyme as mumoles of androstenedione produced/microgram DNA/h. The reaction is limited to 0.5 - 4 micrograms DNA of Leydig cells/ml (equivalent to 0.1-0.8 million of Leydig cells/ml) and to 1 h of incubation at 34 degree C. The 3 beta-HSD activity of 44 suspensions of Leydig cells isolated from adult rats was found to be 1.13 +/- 0.03 (SE) mumoles/microgram DNA/h. This new method for direct measurement of 3 beta-HSD activity in intact Leydig cells was found to be rapid, easy to perform and highly reproducible.
D015096:3-Hydroxysteroid Dehydrogenases / Q000032:analysis*; D000735:Androstenedione / Q000378:metabolism; D000818:Animals; D003687:Dehydroepiandrosterone / Q000378:metabolism; D007985:Leydig Cells / Q000201:enzymology*; D008297:Male; D008722:Methods; D051381:Rats; D011919:Rats, Inbred Strains
D000735:Androstenedione; D003687:Dehydroepiandrosterone; D015096:3-Hydroxysteroid Dehydrogenases