Goedecke J H, Levitt N S, St Clair Gibson A, Grobler L, Noakes T D, Lambert E V
UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Newlands, South Africa.
Metabolism. 2001 Nov;50(11):1286-93. doi: 10.1053/meta.2001.27226.
The aim of this study was to examine the role of fasting insulin concentrations and tissue insulin sensitivity on whole-body substrate oxidation in 61 well-trained subjects. Subjects underwent a frequently sampled intravenous glucose tolerance test (FSIVGT) after a 10- to 12-hour overnight fast. Minimal model analysis was used to determine insulin sensitivity (S(i)). A week later, fasting (10- to 12-hour) respiratory exchange ratio (RER) was measured at rest and during exercise at 25%, 50%, and 70% of peak power output (W(peak)). Prior to these measurements, training volume, dietary intake, and muscle fiber composition, substrate concentrations, and enzyme activities were determined. The average fasting plasma insulin concentration was 7.3 +/- 2.4 microU/mL (4.0 to 10.5 microU/mL), and the mean S(i) was 14.0 +/- 6.1 x (10(-4) min(-1) x microU(-1) x mL(-1)) (2.6 to 26.3 x 10(-4) min(-1) x microU(-1) x mL(-1)). There was no significant correlation between fasting plasma insulin concentration and S(i) (r = -.14, P =.336) or between these measurements and fasting RER, measured at rest and during exercise at 25%, 50%, and 70% W(peak). Only VO(2max) and the proportion of type 1 muscle fibers were significantly correlated with S(i) (r =.30, P =.045 and r =.34, P =.026, respectively), and waist-to-hip ratio (WHR) was significantly correlated with fasting plasma insulin concentration (r =.35, P =.006). In conclusion, S(i) and fasting plasma insulin concentration were not associated with fasting RER at rest and during exercise of increasing intensity in trained athletes who have high S(i).
本研究的目的是在61名训练有素的受试者中，检验空腹胰岛素浓度和组织胰岛素敏感性对全身底物氧化的作用。受试者在禁食10至12小时的过夜空腹后，接受了频繁采样的静脉葡萄糖耐量试验（FSIVGT）。采用最小模型分析法来确定胰岛素敏感性（S(i)）。一周后，在静息状态以及运动强度分别为峰值功率输出（W(peak)）的25%、50%和70%时，测量空腹（10至12小时）呼吸交换率（RER）。在进行这些测量之前，测定了训练量、饮食摄入量、肌纤维组成、底物浓度和酶活性。空腹血浆胰岛素浓度的平均值为7.3±2.4微单位/毫升（4.0至10.5微单位/毫升），平均S(i)为14.0±6.1×（10(-4)分钟(-1)×微单位(-1)×毫升(-1)）（2.6至26.3×10(-4)分钟(-1)×微单位(-1)×毫升(-1)）。空腹血浆胰岛素浓度与S(i)之间无显著相关性（r = -0.14，P = 0.336），在静息状态以及运动强度为W(peak)的25%、50%和70%时测量的空腹RER与这些测量值之间也无显著相关性。只有最大摄氧量（VO(2max)）和I型肌纤维比例与S(i)显著相关（r分别为0.30，P = 0.045和r = 0.34，P = 0.026），腰臀比（WHR）与空腹血浆胰岛素浓度显著相关（r = 0.35，P = 0.006）。总之，在胰岛素敏感性较高的训练有素的运动员中，S(i)和空腹血浆胰岛素浓度与静息状态以及运动强度增加时的空腹RER无关。
