Pratt Shannon E, Geor Ray J, McCutcheon L Jill
Department of Animal and Poultry Science, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1.
J Vet Intern Med. 2005 Nov-Dec;19(6):883-8. doi: 10.1892/0891-6640(2005)19[883:romfao]2.0.co;2.
Both the euglycemic-hyperinsulinemic clamp (EHC) and minimal model analysis of the frequently sampled intravenous glucose tolerance test (FSIGT) have been applied for measurement of insulin sensitivity in horses. However, no published data are available on the reproducibility of these methods. Therefore, the objective of this study was to evaluate the variation and repeatability of measures of glucose dynamics and insulin sensitivity in horses derived from minimal model analysis of the FSIGT and from the EHC method. Six healthy horses underwent both the FSIGT and EHC on 2 occasions over a 4-week period, with a minimum of 5 days between tests. Coefficient of variation (CV) and intraclass correlation coefficient (ICC) were calculated for measures of glucose metabolism and insulin sensitivity derived from each test. In the EHC, insulin sensitivity, expressed as the amount of metabolized glucose (M) per unit of serum insulin (I) (M/I ratio), averaged 0.19 +/- 0.06 x 10(-4) mmol/kg/min x (pmol/L)(-1) with an average interday CV of 14.1 +/- 5.7% (range, 7-20%) and ICC of 0.74. Minimal model analysis of the FSIGT demonstrated mean insulin sensitivity (Si) of 0.49 +/- 0.17 x 10(-4)/min x (pmol/L)(-1) with an average interday CV of 23.7 +/- 11.2% (range, 9-35%) and ICC of 0.33. Mean CV and ICC for minimal model glucose effectiveness (Sg) and acute insulin response (AIRg) were, respectively, 26.4 +/- 11.2% (range 13-40%) and 0.10 and 11.7 +/- 6.5% (range 7-21%) and 0.98. Insulin sensitivity measured by the EHC has lower interday variation when compared with the minimal model estimate derived from the FSIGT.
正常血糖-高胰岛素钳夹试验（EHC）和频繁采样静脉葡萄糖耐量试验（FSIGT）的最小模型分析均已应用于马匹胰岛素敏感性的测定。然而，尚无关于这些方法可重复性的已发表数据。因此，本研究的目的是评估通过FSIGT的最小模型分析和EHC方法得出的马匹葡萄糖动力学和胰岛素敏感性测量值的变异性和可重复性。6匹健康马匹在4周内分2次进行了FSIGT和EHC，两次测试之间至少间隔5天。计算了每次测试得出的葡萄糖代谢和胰岛素敏感性测量值的变异系数（CV）和组内相关系数（ICC）。在EHC中，胰岛素敏感性以每单位血清胰岛素（I）代谢的葡萄糖量（M）表示（M/I比值），平均为0.19±0.06×10⁻⁴ mmol/kg/min×(pmol/L)⁻¹，日间平均CV为14.1±5.7%（范围为7 - 20%），ICC为0.74。FSIGT的最小模型分析显示平均胰岛素敏感性（Si）为0.49±0.17×10⁻⁴/min×(pmol/L)⁻¹，日间平均CV为23.7±11.2%（范围为9 - 35%），ICC为0.33。最小模型葡萄糖效能（Sg）和急性胰岛素反应（AIRg）的平均CV和ICC分别为26.4±11.2%（范围为13 - 40%）和0.10以及11.7±6.5%（范围为7 - 21%）和0.98。与从FSIGT得出的最小模型估计值相比，通过EHC测量的胰岛素敏感性日间变异性更低。
