衰老对雄性大鼠睾丸类固醇合成功能的影响

Effects of aging on testicular steroidogenic function in rats

目的:研究老年SD大鼠睾丸类固醇急性调节蛋白(StAR)、17β-羟类固醇脱氢酶(17β-HSD)和芳香化酶(P450arom)的变化,探讨衰老对睾丸类固醇合成的影响。方法:用人绒毛膜促性腺激素(hCG)连续刺激青年和老年雄性SD大鼠,测定基础状态和hCG刺激后血清睾酮(T)和雌二醇(E2)水平,睾丸StAR mRNA、17β-HSDⅢ和P450arom mRNA的表达。结果:(1)基础状态和hCG刺激后,老年SD大鼠血清T水平、17β-HSDⅢmRNA的表达显著低于青年大鼠(P<0.05,P<0.01)。老年SD大鼠StAR mRNA表达降低不明显。(2)老年大鼠血清E2／T水平升高(P<0.01),但睾丸P450acrom mRNA表达没有明显变化。结论:衰老雄性大鼠睾丸17β-HSDⅢ的降低可能是睾酮合成减少的主要影响因素。

Objective:To study the changes of testicular steroidogenic acute regulatory protein (StAR), 17β-hydroxys-teroid dehydrogenase (17β-HSD) and aromatase (P450arom) in elder SD rats, exploring the effects of aging on testicular steroidogenic function. Methods:The young male rats and old male rats were treated with human chorionic gonadotropin (hCG) for 3 times and then rat serum testosterone(T) and estradiol(E2) levels were determined by chemiluminescentenzyme immunoassay(CLIA) and the mRNA levels of StAR, 17β-HSD Ⅲ and P450arom were determined by RT-PCR. Results: (1) The levels of serum T and 17β-HSD Ⅲ mRNA of old SD rats were significantly lower than those of young rats before and after hCG stimulation (P<0. 05), but the StAR mRNA levels of old testes were similar as those young testes; (2)The ratio of serum T and E2 increased in the old rats(P<0. 01), but the levels of P450acrom mRNA of old testes were similar as those young testes. Conclusion: The age-related lose of steroidogenic function may be resulted from decreased level of 17β-HSD Ⅲ .