Mayer M, Rosen F
Am J Physiol. 1975 Nov;229(5):1381-6. doi: 10.1152/ajplegacy.1975.229.5.1381.
While glucocorticoid hormones act catabolically on skeletal muscle through their binding to glucocorticoid-specific receptors in the cytosol, androgens exert anabolic responses but no androgen-specific binding proteins could be detected in this responsive tissue. However, various nonradioactive androgens were effective in displacing labeled dexamethasone or cortisol from their respective cytoplasmic receptors in muscle, both in vitro and in vivo. The inhibition of glucocorticoid binding by androgens is competitive, and could be observed following a single or repeated administration of the androgens to adrenalectomized-castrated animals. The synthetic androgen fluoxymesterone and the hormone testosterone displayed Ki values of 7.5 X 10(-6) M and 1 X 10(-5) M, respectively, for the inhibition of [3H]dexamethasone binding in muscle cytosol. On the basis of competition experiments it is postulated that interaction of androgens with glucocorticoid receptors prevents the binding of glucocorticoids and might be responsible in part for the anabolic effects of pharmacologic doses of androgens in muscle.
糖皮质激素通过与胞质溶胶中的糖皮质激素特异性受体结合，对骨骼肌起分解代谢作用，而雄激素则产生合成代谢反应，但在这种反应性组织中未检测到雄激素特异性结合蛋白。然而，各种非放射性雄激素在体外和体内均能有效地将标记的地塞米松或皮质醇从肌肉中各自的细胞质受体上置换下来。雄激素对糖皮质激素结合的抑制作用是竞争性的，在对肾上腺切除-去势动物单次或重复给予雄激素后均可观察到。合成雄激素氟甲睾酮和激素睾酮对肌肉胞质溶胶中[3H]地塞米松结合的抑制作用的Ki值分别为7.5×10(-6)M和1×10(-5)M。基于竞争实验推测，雄激素与糖皮质激素受体的相互作用会阻止糖皮质激素的结合，这可能部分解释了药理剂量的雄激素在肌肉中的合成代谢作用。
