Effect of gossypol on 5 alpha-reductase and 3 alpha-hydroxysteroid dehydrogenase activities in adult rat testes.
Effect of gossypol on 5 alpha-reductase and 3 alpha-hydroxysteroid dehydrogenase activities in adult rat testes.
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发表时间：
1993-10
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通讯作者：
P. P. Moh-P.;G. C. Chang;R. Brueggemeier;Y. C. Lin
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作者：
P. P. Moh-P.;G. C. Chang;R. Brueggemeier;Y. C. Lin
据报道，当孕酮用作底物时，在成年大鼠睾丸中几乎检测不到5 α-还原酶。本文研究了4月龄大鼠5 α-还原酶活性及棉酚对甾体合成的抑制作用。睾丸切片（10微米厚）在NADPH存在下于30.5 ℃下孵育，其中3 H-睾酮和冷睾酮作为底物（总共9 μ M），并分别含有或不含有棉酚作为测试样品和对照。内源性睾酮水平用放射免疫法测定。采用反相高效液相色谱（HPLC）分离底物和产物。收集感兴趣的组分并监测其回收率。在200 μ M浓度下，与对照相比（0.6 μ m/mg蛋白质/min），棉酚显著降低二氢睾酮（DHT）形成21%，并且与对照相比（2 μ m/mg蛋白质/min），降低5 α-雄甾烷-3 α，17 β-二醇形成35%。在目前的研究中，发现棉酚对5 α-还原酶和3 α-羟基类固醇脱氢酶（3 α-HSD）具有非竞争性抑制作用，5 α-还原酶催化睾酮转化为DHT，3 α-HSD使DHT和二氢雄甾烷相互转化。
It has been reported that little to no 5 alpha-reductase can be detected in adult rat testes when progesterone is used as substrate. The 5 alpha-reductase activity in 4-month-old rats and the inhibitory action of gossypol on steroidobiosynthesis were studied. Testicular sections (10 microns thickness) were incubated at 30.5 degrees C in the presence of NADPH with 3H-testosterone and cold testosterone as substrates (9 microM total), and with or without gossypol as the test sample and control, respectively. Endogenous testosterone level was evaluated by radioimmunoassay. Reverse phase high performance liquid chromatography (HPLC) was used to separate the substrate and products. Components of interest were collected and their recovery monitored. At 200 microM concentration, gossypol significantly decreased dihydrotestosterone (DHT) formation by 21% when compared to that of control (0.6 pm/mg protein/min), and decreased 5 alpha-androstane-3 alpha,17 beta-diol formation by 35% vs control (2 pm/mg protein/min). In the current study, gossypol was found to have inhibitory effects of noncompetitive nature on 5 alpha-reductase, which catalyzes the conversion of testosterone to DHT, and on 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSD), which interconverts DHT and dihydroandrostanediol.