Zachwieja J J, Toffolo G, Cobelli C, Bier D M, Yarasheski K E
Pennington Biomedical Research Center, Louisiana State University, Baton Rouge 70808, USA.
Metabolism. 1996 Feb;45(2):254-60. doi: 10.1016/s0026-0495(96)90063-3.
To assess the effects of 16 weeks of heavy resistance exercise training (RE) on insulin sensitivity and secretion in healthy older men aged 64 to 75 years (N = 15), stable-label ([6,6,2H2]glucose) intravenous glucose tolerance tests (IVGTTs) were performed before and 7 days after the last bout of exercise. Glucose disappearance rate (Rd) and an index of insulin sensitivity (Si*) were derived using the minimal model of labeled glucose disappearance, and insulin secretion parameters were derived from C-peptide and glucose concentrations measured during the IVGTT, using a minimal model of C-peptide secretion and kinetics. Each subject trained at an intensity of 70% to 95% maximum strength 4 d/wk for 16 weeks on Nautilus (DeLand, FL) weight-training equipment. In conjunction with exercise, six men received daily injections of recombinant human growth hormone ([rhGH] 12.5 to 24 microg/kg/d) and the other nine received placebo injections. GH/placebo injections were administered in a double-blind randomized fashion. The RE program was supervised and progressive in nature, consisting of both upper-and lower-body exercises, and significantly increased muscle strength (P < .05) with no additional benefit from rhGH except for a tendency toward a greater increase in fat-free mass (FFM) in the RE + GH group (P = .06). Peak glucose Rd increased following RE (P < 01), and there was a trend for an improved Si* (ie, from 6.79 +/- 1.14 to 8.42 +/- 0.89 x 10(4) per min/[microU/mL], P = .06). Peak glucose Rd and Si* were unchanged in the RE + GH group following treatment. First- and second-phase insulin secretion were not affected by RE or RE + GH. Glucose tolerance, quantified as the glucose disappearance constant (Kg) between 10 and 32 minutes of the IVGTT, was unchanged by exercise or hormone treatment. These findings support those of a recent study that used the hyperinsulinemic-euglycemic clamp technique (Miller et al, J Appl Physiol 77:1122-1127, 1994), and suggest that when healthy older men engage in RE, whole-body glucose Rd and Si* are improved, and these beneficial effects are not only due to the acute effects of the last bout of exercise. Additionally, in six subjects who received GH, glucose Rd and Si* were not significantly improved following the RE program. Although this may suggest that GH can diminish improvements in glucose Rd and Si* that result from RE, further study is needed to confirm this observation.
为评估16周的大强度抗阻运动训练（RE）对64至75岁健康老年男性（N = 15）胰岛素敏感性和分泌的影响，在最后一次运动前及运动后7天进行了稳定同位素标记（[6,6,2H2]葡萄糖）静脉葡萄糖耐量试验（IVGTT）。使用标记葡萄糖消失的最小模型得出葡萄糖消失率（Rd）和胰岛素敏感性指数（Si*），并使用C肽分泌和动力学的最小模型，从IVGTT期间测量的C肽和葡萄糖浓度得出胰岛素分泌参数。每位受试者每周4天以70%至95%最大力量的强度在诺德士（佛罗里达州德兰市）重量训练设备上训练16周。在运动的同时，6名男性每天注射重组人生长激素（[rhGH] 12.5至24微克/千克/天），另外9名接受安慰剂注射。GH/安慰剂注射采用双盲随机方式给药。RE计划具有监督性且是循序渐进的，包括上身和下身运动，显著增加了肌肉力量（P <.05），除了RE + GH组无脂肪体重（FFM）有更大增加的趋势外（P =.06），rhGH没有额外益处。RE后峰值葡萄糖Rd增加（P < 0.01），并且Si有改善趋势（即从6.79 +/- 1.14至/分钟/[微单位/毫升] 8.42 +/- 0.89 x 10(4)，P =.06）。治疗后RE + GH组的峰值葡萄糖Rd和Si未改变。第一相和第二相胰岛素分泌不受RE或RE + GH影响。以IVGTT 10至32分钟之间的葡萄糖消失常数（Kg）量化的葡萄糖耐量，不受运动或激素治疗影响。这些发现支持了最近一项使用高胰岛素-正葡萄糖钳夹技术的研究结果（米勒等人，《应用生理学杂志》77:1122 - 1127，1994），并表明当健康老年男性进行RE时，全身葡萄糖Rd和Si得到改善，且这些有益效果不仅归因于最后一次运动的急性效应。此外，在接受GH的6名受试者中，RE计划后葡萄糖Rd和Si没有显著改善。尽管这可能表明GH会削弱RE导致的葡萄糖Rd和Si*的改善，但需要进一步研究来证实这一观察结果。
