Haus J M, Miller B F, Carroll C C, Weinheimer E M, Trappe T A
Human Performance Laboratory, Ball State University, Muncie, Indiana 47306, USA.
Scand J Med Sci Sports. 2007 Jun;17(3):260-6. doi: 10.1111/j.1600-0838.2006.00566.x. Epub 2006 Jun 19.
Relatively little is known about the dynamics of the skeletal muscle protein pool following aerobic exercise. Myofibrillar protein synthesis has recently been shown to be substantially elevated for 3 days after a strenuous 60 min bout of one-legged aerobic exercise, and this increase was surprisingly equal to or greater than what has been shown numerous times following resistance exercise over the same time course. Because net protein accretion is the sum of protein synthesis and degradation, we sought to directly measure skeletal muscle myofibrillar proteolysis in five healthy young males in response to an identical strenuous 60 min aerobic exercise bout and at the same time points (rest, 6, and 24 h post-exercise and 48 and 72 h post-exercise in a subset of subjects). We measured skeletal muscle myofibrillar proteolysis by monitoring the release of the natural tracer 3-methylhistidine (3MH) from the vastus lateralis muscle into the interstitial space via microdialysis. Skeletal muscle interstitial 3MH concentration was no different (P>0.05) from rest (5.16+/-0.38 nmol/mL) after 6 (5.37+/-0.55 nmol/mL), 24 (5.40+/-0.26 nmol/mL), 48 (5.50+/-0.74 nmol/mL), or 72 h (4.73+/-0.28 nmol/mL). These results suggest that proteolysis of the myofibrillar fraction of skeletal muscle is relatively refractory to an intense aerobic exercise stimulus for up to 3 days, despite the large increase in synthesis of this muscle fraction following the same exercise stimulus. The apparent net myofibrillar protein accretion in the hours and days after exercise may occur in order to offset the large elevation in mixed muscle proteolysis that has been shown during similar bouts of intense one-legged aerobic exercise.
关于有氧运动后骨骼肌蛋白池的动态变化，人们了解得相对较少。最近的研究表明，在进行60分钟剧烈的单腿有氧运动后，肌原纤维蛋白合成在3天内会显著升高，而且这一增幅惊人地等于或大于在相同时间内多次进行抗阻运动后的增幅。由于净蛋白增加是蛋白合成与降解的总和，我们试图直接测量五名健康年轻男性在进行相同的60分钟剧烈有氧运动后，以及在相同时间点（休息时、运动后6小时和24小时，部分受试者在运动后48小时和72小时）骨骼肌肌原纤维的蛋白水解情况。我们通过微透析监测天然示踪剂3-甲基组氨酸（3MH）从股外侧肌释放到间质空间的情况，以此来测量骨骼肌肌原纤维的蛋白水解。在运动后6小时（5.37±0.55纳摩尔/毫升）、24小时（5.40±0.26纳摩尔/毫升）、48小时（5.50±0.74纳摩尔/毫升）或72小时（4.73±0.28纳摩尔/毫升），骨骼肌间质3MH浓度与休息时（5.16±0.38纳摩尔/毫升）相比无差异（P>0.05）。这些结果表明尽管在相同运动刺激后该肌肉部分的合成大幅增加，但在长达3天内，骨骼肌肌原纤维部分的蛋白水解对剧烈有氧运动刺激相对不敏感。运动后数小时和数天内明显的肌原纤维净蛋白增加可能是为了抵消在类似的剧烈单腿有氧运动期间所显示的混合肌肉蛋白水解大幅升高的情况。
