Watanabe R M, Lovejoy J, Steil G M, DiGirolamo M, Bergman R N
University of Southern California, Department of Exercise Science, USA.
Diabetes. 1995 Aug;44(8):954-62. doi: 10.2337/diab.44.8.954.
Mathematical modeling was used to explore the interaction between glucose, insulin, and lactate during the frequently sampled intravenous glucose tolerance test (FSIGTT). Insulin-modified FSIGTs were performed in 25 lean volunteers, and an additional 5 volunteers underwent FSIGTs with glucose injection alone to illustrate the effect of insulin on both glucose and lactate kinetics. The model chosen as the best representation of the system extended the minimal model of glucose kinetics (MM) by including a two-compartment model of lactate kinetics. The model accounted for both glucose and lactate kinetics, provided traditional MM parameters of insulin sensitivity and glucose effectiveness, and descriptive parameters of lactate kinetics. Modeling suggested that lactate production was limited by the rate of glucose disappearance, with no indication of direct effects of insulin on lactate. Inclusion of lactate kinetics had no adverse effect on MM parameters (SG: 0.023 +/- 0.009 vs. 0.023 +/- 0.010 min-1, SI: 1.01 +/- 0.70 vs. 1.03 +/- 0.71 x 10(4).min-1.pmol-1.1; P > 0.50, lactate model vs. MM), and indicated that approximately 1.2% min-1 of total glucose disappearance during the FSIGT is converted to lactate. An additional benefit of including lactate kinetics was the significant improvement in precision in MM parameter estimates as reflected by the fractional standard deviations (FSDs). This effect was most prominent for SG, in which a threefold improvement in parameter precision was observed (FSD: 13.5 +/- 3.1 vs. 42.5 +/- 48.5; means +/- SD).(ABSTRACT TRUNCATED AT 250 WORDS)
采用数学建模方法，在频繁采样静脉葡萄糖耐量试验（FSIGTT）期间探究葡萄糖、胰岛素和乳酸之间的相互作用。对25名瘦志愿者进行了胰岛素改良的FSIGT，另外5名志愿者仅接受葡萄糖注射的FSIGT，以阐明胰岛素对葡萄糖和乳酸动力学的影响。被选为系统最佳代表的模型，通过纳入乳酸动力学的两室模型扩展了葡萄糖动力学的最小模型（MM）。该模型兼顾了葡萄糖和乳酸动力学，提供了胰岛素敏感性和葡萄糖有效性的传统MM参数以及乳酸动力学的描述性参数。建模表明，乳酸生成受葡萄糖消失速率的限制，没有迹象表明胰岛素对乳酸有直接影响。纳入乳酸动力学对MM参数没有不利影响（SG：0.023±0.009对0.023±0.010 min⁻¹，SI：1.01±0.70对1.03±0.71×10⁴.min⁻¹.pmol⁻¹.1；P＞0.50，乳酸模型对MM），并表明在FSIGT期间，约1.2% min⁻¹的总葡萄糖消失转化为乳酸。纳入乳酸动力学的另一个好处是，如分数标准差（FSD）所示，MM参数估计的精度有显著提高。这种效应在SG中最为显著，观察到参数精度提高了三倍（FSD：13.5±3.1对42.5±48.5；均值±标准差）。（摘要截断于250字）
