Cellular localization of 5alpha-reductase and 3alpha-hydroxysteroid dehydrogenase in the seminiferous tubule of the rat testis.
Cellular localization of 5alpha-reductase and 3alpha-hydroxysteroid dehydrogenase in the seminiferous tubule of the rat testis.
复制标题
大鼠睾丸生精小管中 5α-还原酶和 3α-羟基类固醇脱氢酶的细胞定位。
作者：
J. Dorrington;I. Fritz
从正常成年大鼠分离的生精小管将(14C)睾酮转化为(14C)雄烷二醇和(14C)雄烯二酮作为主要代谢物； (14C)二氢睾酮和(14C)雄酮的产生量较少。与成年大鼠的肾小管相比，未成熟大鼠（26-28 天龄）的肾小管将更高比例的 (14C) 睾酮转化为 5α 还原产物。富含精母细胞的制剂含有 5α-还原酶。精子细胞-精母细胞制剂中 5α-还原酶活性水平较低，表明精子细胞中该酶含量较低或不存在。富含支持细胞的制剂含有 5α-还原酶和高水平的 3α-羟基类固醇脱氢酶。结果表明，精母细胞和支持细胞具有将（14C）睾酮代谢为 5α 还原产物的能力；二氢睾酮是精母细胞形成的主要产物，而在支持细胞中进一步代谢为5α-雄甾烷-3α、17β-二醇。
Seminiferous tubules isolated from normal adult rats converted (14C) testosterone to (14C) androstanediol and (14C) androstenedione as the major metabolites; (14C) dihydrotestosterone and (14C) androsterone were produced in lesser amounts. Tubules from immature rats (26-28 days of age) converted a higher proportion of (14C) testosterone to 5alpha-reduced products than did tubules from adult rats. Spermatocyte-enriched preparations contain 5alpha-reductase. The lower level of 5alpha-reductase activity in spermatid-spermatocyte preparations indicates that this enzyme is low or absent in spermatids. Sertoli cell-enriched preparations contain 5 alpha-reductase and a high level of 3alpha-hydroxysteroid dehydrogenase. The results show that spermatocytes and Sertoli cells have the capacity to metabolise (14C) testosterone to 5alpha-reduced products; dihydrotesterone is the major product formed by spermatocytes, whereas in Sertoli cells further metabolism to 5alpha-androstane-3alpha, 17beta-diol occurs.