Nordsborg Nikolai, Goodmann Craig, McKenna Michael J, Bangsbo Jens
August Krogh Institute, Institute of Exercise and Sport Sciences, Universitetsparken 13, 2. floor, 2100 Copenhagen, Denmark.
J Physiol. 2005 Sep 1;567(Pt 2):583-9. doi: 10.1113/jphysiol.2005.087031. Epub 2005 Jun 23.
Dexamethasone, a widely clinically used glucocorticoid, increases human skeletal muscle Na+,K+ pump content, but the effects on maximal Na+,K+ pump activity and subunit specific mRNA are unknown. Ten healthy male subjects ingested dexamethasone for 5 days and the effects on Na+,K+ pump content, maximal activity and subunit specific mRNA level (alpha1, alpha2, beta1, beta2, beta3) in deltoid and vastus lateralis muscle were investigated. Before treatment, maximal Na+,K+ pump activity, as well as alpha1, alpha2, beta1 and beta2 mRNA levels were higher (P < 0.05) in vastus lateralis than in deltoid. Dexamethasone treatment increased Na+,K+ pump maximal activity in vastus lateralis and deltoid by 14 +/- 7% (P < 0.05) and 18 +/- 6% (P < 0.05) as well as Na+,K+ pump content by 18 +/- 9% (P < 0.001) and 24 +/- 8% (P < 0.01), respectively. Treatment with dexamethasone resulted in a higher alpha1, alpha2, beta1 and beta2 mRNA expression in the deltoid (P < 0.05), but no effects on Na+,K+ pump mRNA were detected in vastus lateralis. In conclusion, dexamethasone treatment increased maximal Na+,K+ pump activity in both vastus lateralis and deltoid muscles. The relative importance of transcription and translation in the glucocorticoid-induced regulation of Na+,K+ pump expression seems to be muscle specific and possibly dependent on the actual training condition of the muscle, such that a high Na+,K+ pump maximal activity and mRNA level prior to treatment prevents the transcriptional response to dexamethasone, but not the increase in Na+,K+ pump content and maximal activity.
地塞米松是一种临床广泛使用的糖皮质激素，可增加人体骨骼肌钠钾泵含量，但对最大钠钾泵活性和亚基特异性mRNA的影响尚不清楚。10名健康男性受试者服用地塞米松5天，并研究其对三角肌和股外侧肌中钠钾泵含量、最大活性和亚基特异性mRNA水平（α1、α2、β1、β2、β3）的影响。治疗前，股外侧肌的最大钠钾泵活性以及α1、α2、β1和β2 mRNA水平高于三角肌（P<0.05）。地塞米松治疗使股外侧肌和三角肌的钠钾泵最大活性分别增加14±7%（P<0.05）和18±6%（P<0.05），钠钾泵含量分别增加18±9%（P<0.001）和24±8%（P<0.01）。地塞米松治疗导致三角肌中α1、α2、β1和β2 mRNA表达升高（P<0.05），但在股外侧肌中未检测到对地塞米松对钠钾泵mRNA的影响。总之，地塞米松治疗增加了股外侧肌和三角肌的最大钠钾泵活性。糖皮质激素诱导的钠钾泵表达调节中转录和翻译的相对重要性似乎具有肌肉特异性，可能取决于肌肉的实际训练状态，使得治疗前高钠钾泵最大活性和mRNA水平可阻止对地塞米松的转录反应，但不能阻止钠钾泵含量和最大活性的增加。
