Gulve E A, Spina R J
Department of Medicine, Washington University School of Medicine, St Louis, Missouri 63110, USA.
J Appl Physiol (1985). 1995 Nov;79(5):1562-6. doi: 10.1152/jappl.1995.79.5.1562.
Previous studies in animals and humans have shown that endurance exercise-training protocols of several weeks to many months in duration induce adaptive increases in skeletal muscle GLUT-4 protein concentration. It is generally assumed that the increase in GLUT-4 concentration is a long-term adaptation to training. The present study examined whether 7-10 days of cycle ergometer exercise could induce increases in skeletal muscle GLUT-4 levels. Eight healthy subjects (4 men, 4 women) aged 31 +/- 2 (SE) yr exercised 2 h daily at 65-70% of peak O2 uptake (VO2peak) for either 7 (n = 3) or 10 (n = 5) consecutive days. Muscle biopsies (vastus lateralis) were obtained before initiation of the exercise program and 36-48 h after the final bout of exercise. Glucose transporter protein was quantitated by Western blotting using antiserum specific for GLUT-4. VO2peak was increased by 10% (from 3.0 +/- 0.2 to 3.3 +/- 0.2 l/min; P < 0.01) in response to the training. Body weight did not change (74.3 +/- 4.6 before vs. 75.0 +/- 4.2 kg after) as a result of training. Muscle GLUT-4 immunoreactivity was increased 98% (from 584 +/- 50 to 1,154 +/- 40 counts per minute 125I/25 micrograms protein; P < 0.001) in response to training. Increase in VO2peak and GLUT-4 protein were similar for 7 and 10 days of training. These results suggest that, given an adequate training stimulus, adaptations in skeletal muscle GLUT-4 protein occur very rapidly. Furthermore, the increase in GLUT-4 after 7-10 days of exercise is as large as that reported in studies employing long-term training protocols.
先前在动物和人类身上进行的研究表明，持续数周乃至数月的耐力运动训练方案会使骨骼肌中葡萄糖转运蛋白4（GLUT-4）的蛋白质浓度适应性增加。一般认为，GLUT-4浓度的增加是对训练的一种长期适应性变化。本研究探讨了为期7至10天的蹬车测力计运动是否能促使骨骼肌中GLUT-4水平升高。8名年龄为31±2（标准误）岁的健康受试者（4名男性，4名女性），连续7天（n = 3）或10天（n = 5），每天以峰值摄氧量（VO₂peak）的65%至70%进行2小时的运动。在运动计划开始前以及最后一次运动结束后的36至48小时采集肌肉活检样本（股外侧肌）。使用对GLUT-4具有特异性的抗血清，通过蛋白质免疫印迹法对葡萄糖转运蛋白进行定量分析。训练后，VO₂peak增加了10%（从3.0±0.2升至3.3±0.2升/分钟；P < 0.01）。训练后体重未发生变化（训练前为74.3±4.6千克，训练后为75.0±4.2千克）。训练后，肌肉GLUT-4免疫反应性增加了98%（从每分钟584±50计数升至125I/25微克蛋白质的1,154±40计数；P < 0.001）。7天和10天训练的VO₂peak增加量以及GLUT-4蛋白增加量相似。这些结果表明，在给予足够训练刺激的情况下，骨骼肌中GLUT-4蛋白的适应性变化出现得非常迅速。此外，7至10天运动后GLUT-4的增加幅度与采用长期训练方案的研究中所报道的幅度一样大。
