James D E, Kraegen E W, Chisholm D J
J Appl Physiol Respir Environ Exerc Physiol. 1984 May;56(5):1217-22. doi: 10.1152/jappl.1984.56.5.1217.
Exercise training causes a decline in basal and glucose-stimulated plasma insulin levels and improves glucose tolerance. Furthermore evidence has been presented for effects on both insulin receptors and postreceptor events. However, it is unclear how these changes affect the in vivo dose-response relationship between insulin levels and whole-body glucose utilization. The aim was to examine the effect of exercise training on this relationship and distinguish between changes in insulin sensitivity and responsiveness. Euglycemic clamps were performed in trained (ET, running 1 h/day for 7 wk), sedentary (CON), and sedentary food-restricted ( SFR ) rats. ET rats showed no increase in maximal net glucose utilization in response to insulin (ET 29.5 +/- 0.6 vs. CON 28.2 +/- 1.5 mg X kg-1 X min-1, NS), whereas insulin sensitivity was increased as indicated by the insulin concentration causing half-maximal stimulation (ED50) (49 +/- 20 for ET and 133 +/- 30 mU/l for CON). Thus 7 wk of moderate exercise training resulted in a significant shift of whole-body insulin sensitivity to place ED50 well within the physiological range of insulin concentrations. This would undoubtedly result in improved glucose disposal in the postprandial state and emphasizes the potential benefit of exercise in obesity and type II diabetes.
运动训练会导致基础血浆胰岛素水平和葡萄糖刺激后的血浆胰岛素水平下降，并改善葡萄糖耐量。此外，已有证据表明运动训练对胰岛素受体和受体后事件均有影响。然而，目前尚不清楚这些变化如何影响胰岛素水平与全身葡萄糖利用之间的体内剂量反应关系。本研究旨在探讨运动训练对这种关系的影响，并区分胰岛素敏感性和反应性的变化。对经过训练的大鼠（ET组，每天跑步1小时，持续7周）、久坐不动的大鼠（CON组）和久坐且食物受限的大鼠（SFR组）进行了正常血糖钳夹实验。ET组大鼠对胰岛素的最大净葡萄糖利用率没有增加（ET组为29.5±0.6，CON组为28.2±1.5 mg·kg-1·min-1，无显著性差异），而胰岛素敏感性增加，这可由引起半数最大刺激的胰岛素浓度（ED50）来表明（ET组为49±20，CON组为133±30 mU/l）。因此，7周的中等强度运动训练导致全身胰岛素敏感性显著改变，使ED50完全处于胰岛素浓度的生理范围内。这无疑会使餐后状态下的葡萄糖处理得到改善，并强调了运动对肥胖和II型糖尿病的潜在益处。
