Localization of delta 4-5 beta- and 5 alpha-reductases and 17 beta-ol-dehydrogenase in immature golden hamster testes.
Testes of 28- and 70-day-old golden hamsters were separated into seminiferus tubules and interstitial tissue by wet dissection. Homogenates of the tissues and subcellular fractions were incubated with [14C]androstenedione, and NADPH and enzyme activity (nanomoles per 100 mg protein/h) was estimated. In immature testes, the 5 beta-reductase activity was largely confined to the seminiferous tubules, while 5 alpha-reductase was localized in the interstitial tissue. The activity of 17 beta-ol-dehydrogenase was found to be equally distributed between tubules and interstitial tissue. Although the activities of 5 beta- and 5 alpha-reductases were approximately 10 times greater in immature than adult testes, the 17 beta-ol-dehydrogenase activity in adult testes was approximately 10 times that in immature testes. In the immature testes, most 5 alpha-reductase and 17 beta-ol-dehydrogenase were localized in microsomes, whereas 5 beta-reductase was wholly localized in cytosol. These results indicates that 5 beta-reduction of delta 4-3-ketosteroids takes place largely in cytosol of tubular cells, while 5 alpha-reduction occurs in microsomes of interstitial cells in the testis of the immature golden hamster.
D015067:17-Hydroxysteroid Dehydrogenases / Q000032:analysis*; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000032:analysis*; D000818:Animals; D006224:Cricetinae; D008297:Male; D008647:Mesocricetus; D008861:Microsomes / Q000201:enzymology; D010088:Oxidoreductases / Q000032:analysis*; D013737:Testis / Q000201:enzymology*; D014018:Tissue Distribution
D010088:Oxidoreductases; D015067:17-Hydroxysteroid Dehydrogenases; C032690:3-alpha-(17-beta)-hydroxysteroid dehydrogenase (NAD(+)); D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase; C021936:3-oxo-5 beta-steroid delta 4-dehydrogenase