Max S R
Department of Neurology, University of Maryland School of Medicine, Baltimore 21201.
Med Sci Sports Exerc. 1990 Jun;22(3):325-30.
We studied the effect of glucocorticoids on glutamine synthetase in rat skeletal muscle in culture and in vivo. Dexamethasone, a synthetic glucocorticoid, caused striking, receptor-mediated increases in both glutamine synthetase activity and the steady-state glutamine synthetase mRNA level. This effect was observed in rat skeletal muscle cells in culture, as well as in rat muscles in vivo. Glucocorticoid-mediated induction of glutamine synthetase was blocked by androgenic/anabolic steroids at high doses, suggesting that anabolic steroids might have an anticatabolic mode of action in enhancing skeletal muscle mass in athletes. Further studies of the control of glutamine synthetase expression may shed light on mechanisms of muscle atrophy and hypertrophy.
我们研究了糖皮质激素对培养的和活体大鼠骨骼肌中谷氨酰胺合成酶的影响。合成糖皮质激素地塞米松导致谷氨酰胺合成酶活性和谷氨酰胺合成酶mRNA稳态水平显著增加，且这种增加是由受体介导的。在培养的大鼠骨骼肌细胞以及活体大鼠肌肉中均观察到了这种效应。高剂量的雄激素/合成代谢类固醇可阻断糖皮质激素介导的谷氨酰胺合成酶诱导作用，这表明合成代谢类固醇在增强运动员骨骼肌质量方面可能具有抗分解代谢的作用模式。对谷氨酰胺合成酶表达调控的进一步研究可能会揭示肌肉萎缩和肥大的机制。
