Green H J, Duhamel T A, Stewart R D, Tupling A R, Ouyang J
Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada, N2L 3G1.
Am J Physiol Endocrinol Metab. 2008 Apr;294(4):E761-7. doi: 10.1152/ajpendo.00751.2007. Epub 2008 Jan 29.
The early plasticity of vastus lateralis Na(+)-K(+)-ATPase to the abrupt onset of prolonged submaximal cycling was studied in 12 untrained participants (Vo(2 peak) 44.8 +/- 2.0 ml x kg(-1) x min(-1), mean +/- SE) using a 6-day protocol (3 days of exercise plus 3 days of recovery). Tissue samples were extracted prior to (Pre) and following exercise (Post) on day 1 (E1) and day 3 (E3) and on each day of recovery (R1, R2, R3) and analyzed for changes in maximal protein (beta(max)) (vanadate-facilitated [(3)H]ouabain binding), alpha- and beta-isoform concentration (quantitative immunoblotting) and maximal Na(+)-K(+)-ATPase activity (V(max)) (3-O-methylfluorescein K(+)-stimulated phosphatase assay). For beta(max) (pmol/g wet wt), an increase (P < 0.05) of 11.8% was observed at R1 compared with E1-Pre (340 +/- 14 vs 304 +/- 17). For the alpha-isoforms alpha(1), alpha(2), and alpha(3), increases (P < 0.05) of 46, 42, and 31% were observed at R1, respectively. For the beta-isoform, beta(1) and beta(2) increased (P < 0.05) by 19 and 28% at R1, whereas beta(3) increased (P < 0.05) by 18% at R2. With the exception of alpha(2) and alpha(3), the increases in the isoforms persisted at R3. Exercise resulted in an average decrease (P < 0.05) in V(max) by 14.3%. No differences were observed in V(max) at E1 - Pre and E3 - Pre or between R1, R2, and R3. It is concluded that 3 days of prolonged exercise is a powerful stimulus for the rapid upregulation of the Na(+)-K(+)-ATPase subunit isoforms. Contrary to our hypothesis, the increase in subunit expression is not accompanied by increases in the maximal catalytic activity.
在12名未经训练的参与者（峰值摄氧量44.8±2.0 ml·kg⁻¹·min⁻¹，均值±标准误）中，采用6天方案（3天运动加3天恢复）研究了股外侧肌钠钾ATP酶对长时间次最大强度骑行突然开始的早期可塑性。在第1天（E1）和第3天（E3）运动前（Pre）和运动后（Post）以及恢复的每一天（R1、R2、R3）采集组织样本，分析最大蛋白（β(max)）（钒酸盐促进的[³H]哇巴因结合）、α和β同工型浓度（定量免疫印迹）以及最大钠钾ATP酶活性（V(max)）（3 - O - 甲基荧光素钾刺激的磷酸酶测定）的变化。对于β(max)（pmol/g湿重），与E1 - Pre相比，R1时观察到增加（P < 0.05）11.8%（340±14对304±17）。对于α同工型α1、α2和α3，R1时分别观察到增加（P < 0.05）46%、42%和31%。对于β同工型，β1和β2在R1时增加（P < 0.05）19%和28%，而β3在R2时增加（P < 0.05）18%。除α2和α3外，同工型的增加在R3时持续存在。运动导致V(max)平均降低（P < 0.05）14.3%。在E1 - Pre和E3 - Pre时或R1、R2和R3之间未观察到V(max)的差异。结论是，3天的长时间运动是钠钾ATP酶亚基同工型快速上调的有力刺激。与我们的假设相反，亚基表达的增加并未伴随着最大催化活性的增加。
