EXERCISE INCREASES MUSCLE GLUT-4 LEVELS AND INSULIN ACTION IN SUBJECTS WITH IMPAIRED GLUCOSE-TOLERANCE
EXERCISE INCREASES MUSCLE GLUT-4 LEVELS AND INSULIN ACTION IN SUBJECTS WITH IMPAIRED GLUCOSE-TOLERANCE
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DOI：
10.1152/ajpendo.1993.264.6.e855
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发表时间：
1993-06-01
影响因子：
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通讯作者：
EVANS, WJ
中科院分区：
文献类型：
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作者：
HUGHES, VA;FIATARONE, MA;EVANS, WJ
胰岛素敏感性下降与衰老、不活动和肥胖有关。运动训练对老年葡萄糖不耐受个体的葡萄糖稳态的影响与体重减轻无关，这一点还没有得到很好的证实。我们研究了运动训练对口服葡萄糖耐量、胰岛素作用和骨骼肌中GLUT-4葡萄糖转运蛋白浓度的影响。在18名个体（年龄= 64 +/- 2，体脂= 37.0 +/- 1.5%）中进行了12周的50%和75%心率储备的运动训练。在最后一次运动后96小时，使用两步高胰岛素-正常葡萄糖钳夹（胰岛素= 192和708 pmol/l）测定外周胰岛素作用。体脂百分比和无脂质量（FFM）在训练中没有变化。通过饮食记录评估的饮食组成在12周内没有变化。观察到口服葡萄糖耐量的改善，表现为训练后较低的血糖浓度（P < 0.05），而血浆胰岛素反应保持不变。在低胰岛素浓度期间，葡萄糖处理率没有变化，但在训练后高胰岛素浓度时增加了11.0%（P < 0.05）（54.4 +/-4.4 vs. 60.4 +/- 5.5 mumol .公斤FFM-1。min-1）。随着训练，骨骼肌糖原和GLUT-4浓度分别增加了24%和60%。GLUT-4蛋白的变化与葡萄糖利用率的变化之间没有直接关系。这些发现表明，在不改变身体成分的情况下，长期运动训练可改善糖耐量受损受试者的外周胰岛素作用。GLUT-4蛋白的变化与胰岛素刺激的葡萄糖处置率之间缺乏统计学显著相关性表明：1）GLUT-4水平可能与运动训练引起的运动诱导的葡萄糖处置变化相关; 2）负责改善葡萄糖稳态的机制是多因素的。
A decline in insulin sensitivity is associated with aging, inactivity, and obesity. The effects of exercise training on glucose homeostasis independent of weight loss in older glucose-intolerant individuals are not well established. We examined the effects of exercise training on oral glucose tolerance, insulin action, and concentration of the GLUT-4 glucose transporters in skeletal muscle. Exercise training at 50 and 75% of heart rate reserve was performed for 12 wk in 18 individuals (age = 64 +/- 2, body fat = 37.0 +/- 1.5%). Peripheral insulin action was determined 96 h after the last exercise bout using a two-step hyperinsulinemic-euglycemic glucose clamp (insulin = 192 and 708 pmol/l). Percent body fat and fat-free mass (FFM) were unchanged with training. Diet composition, assessed by diet record, did not change over the 12 wk. Improved oral glucose tolerance was observed, as exhibited by lower plasma glucose concentrations after training (P < 0.05), whereas plasma insulin response remained unchanged. The rate of glucose disposal was unchanged during the low insulin concentration but increased 11.0% at the high insulin concentration (P < 0.05) after training (54.4 +/- 4,4 vs. 60.4 +/- 5.5 mumol . kg FFM-1 . min-1). Skeletal muscle glycogen and GLUT-4 concentration increased 24 and 60%, respectively, with training. There was no direct relationship between the change in GLUT-4 protein and the change in glucose disposal rate. These findings demonstrate that chronic exercise training without changes in body composition improves peripheral insulin action in subjects with impaired glucose tolerance. The lack of a statistically significant correlation between the changes in GLUT-4 protein and insulin-stimulated glucose disposal rate suggests 1) that GLUT-4 levels may be related instead to changes in exercise-induced glucose disposal resulting from exercise training and 2) that the mechanisms responsible for the improvement in glucose homeostasis are multifactorial.