恒河猴附睾中雄激素浓度及5α还原酶的部分特性分析

Androgen concentration and partial characterization of 5alpha reductase in the epididymis of the rhesus monkey.

作者信息

de Larminat M A, Blaquier J A

出版信息

Steroids. 1978 Jan;31(1):129-38. doi: 10.1016/0039-128x(78)90024-7.

Abstract

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.

摘要

对猴子附睾的5α还原酶活性进行了研究。该酶存在于颗粒状亚细胞组分中，其分布与微粒体标记酶NADPH：细胞色素c还原酶的分布极为相似，这表明5α还原酶与内质网膜有关联。在pH 5.4和32 - 37℃时发现酶活性最高。粗核制剂的Km为0.315×10⁻⁶M，Vmax为168皮摩尔/毫克蛋白质/小时。微粒体酶的Km为0.243×10⁻⁶M，Vmax为828皮摩尔/毫克蛋白质/小时。向孵育介质中添加双氢睾酮（DHT）或5α-雄烷-3α,17β-二醇均不影响这两种酶制剂。2只不同猴子附睾中的内源性雄激素浓度，以纳克/克湿重计为：DHT 20.81±1.98；睾酮（T）：9.01±2.83；二醇：3.03±0.41。