Molecular diversity of 11β-HSDs involved in a protection mechanism from the stress-mediated suppression of testosterone production

11β-羟基类固醇脱氢酶(11β-HSD)同工酶(类型1和类型2)催化生理活性GC和非活性GC的相互转化。用RT-PCR、Western blotting和免疫组织化学染色检测新生猪睾丸和从睾丸中纯化的间质细胞中这些同工酶的存在。在整个睾丸中，与1型相比，2型的表达水平更高。接下来，我们检查了完整的间质细胞中GC代谢的方向，只检测到从皮质醇到皮质醇的氧化。利用间质细胞的微粒体酶制剂，类型2显示出很强的氧化活性，并且活性高于类型1同工酶催化的氧化活性。此外，我们还通过实时荧光RT-PCR法全面检测了11种β-HSD同工酶基因在多种人体组织中的表达。本研究结果表明，β-HSD1型和II型不仅在睾丸间质细胞皮质醇失活中起重要作用，而且参与糖皮质激素抑制睾丸间质细胞睾酮生成的保护作用。

11β-Hydroxysteroid dehydrogenase (11β-HSD) isozyme (type 1 and type 2) catalyze the interconversion of physiologically active GC and inactive forms. The presence of these isozymes was determined in neonatal pig testis and Leydig cells purified from testes by RT-PCR, Western blotting, and immunohistochemical staining. In the entire testis, a higher level of type 2 was expressed compared to type 1. Next, the direction of GC metabolism in intact Leydig cells was examined, and only oxidation from cortisol to cortisone was detected. Using a microsomal enzyme preparation from Leydig cells, type 2 exhibited potent oxidation activity, and the activity was higher than the oxidation activity catalyzed by the type 1 isozyme. Furthermore, we performed comprehensive determination of the expression of 11β-HSD isozymes mRNA by real-time RT-PCR in wide range of human tissues. The results of the present study using testis strongly suggest that not only 11β-HSD type 1 but also type 2 plays important roles in cortisol inactivation in Leydig cells of the testis, and is involved in the protection of glucocorticoid -mediated suppression of testosterone production in Leydig cells of the testis.