Laboratory of Regenerative Medical Engineering, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Steroids. 2010 Mar;75(3):219-23. doi: 10.1016/j.steroids.2009.12.002. Epub 2010 Jan 4.
Androgens, such as testosterone, play important roles in regulation of diverse physiological process of target tissues. Recently, we reported that steroidogenic enzymes exist in skeletal muscle and regulate local production of testosterone in response to exercise. Testosterone is transformed into a bioactive androgen metabolite, dihydrotestosterone (DHT) by 5alpha-reductase. However, it is unclear whether exercise stimulates local bioactive androgen metabolism in the skeletal muscle in both sexes. In the present study, we examined sex differences in the levels of dehydroepiandrosterone (DHEA), free testosterone, DHT, and steroidogenesis-related enzymes 5alpha-reductase and androgen receptor (AR) in rat's skeletal muscle before and after a single bout of exercise. Basal muscular free testosterone and DHT levels were higher in males than females, whereas the levels of DHEA did not differ between the sexes. Muscular DHEA, free testosterone, and DHT levels were increased in both sexes after the exercise. There were no differences of 5alpha-reductase and AR transcripts and proteins between the sexes, and the expression of 5alpha-reductase was significantly increased in both sexes after the exercise. Finally, the expression of AR was significantly higher in female rats, but not in males after the exercise. These data suggest that acute exercise enhances the local bioactive androgen metabolism in the skeletal muscle of both sexes.
雄激素，如睾酮，在调节靶组织的多种生理过程中发挥重要作用。最近，我们报道类固醇生成酶存在于骨骼肌中，并调节运动引起的局部睾酮生成。睾酮被 5α-还原酶转化为生物活性雄激素代谢物二氢睾酮（DHT）。然而，目前尚不清楚运动是否会刺激两性骨骼肌中的局部生物活性雄激素代谢。在本研究中，我们检测了单次运动前后雄性和雌性大鼠骨骼肌中脱氢表雄酮（DHEA）、游离睾酮、DHT 和类固醇生成相关酶 5α-还原酶和雄激素受体（AR）水平的性别差异。基础肌肉游离睾酮和 DHT 水平在雄性中高于雌性，而 DHEA 水平在两性之间没有差异。运动后两性肌肉中的 DHEA、游离睾酮和 DHT 水平均增加。5α-还原酶和 AR 转录本和蛋白在两性之间没有差异，运动后两性 5α-还原酶的表达均显著增加。最后，运动后 AR 的表达在雌性大鼠中显著升高，但在雄性大鼠中没有升高。这些数据表明，急性运动增强了两性骨骼肌中的局部生物活性雄激素代谢。
