Sarson D L, Wood S M, Kansal P C, Bloom S R
Diabetes. 1984 Apr;33(4):389-93. doi: 10.2337/diab.33.4.389.
Glucose-dependent insulinotropic polypeptide (GIP) is said to be a major physiologic factor in the augmentation of the insulin response to oral glucose. Whether GIP promotes insulin release at physiologic concentrations of glucose or GIP, however, is questionable. To investigate this further, volunteers were infused with 10, 20, or 40 g intravenous (i.v.) glucose, with or without simultaneous GIP infusion, to produce plasma levels of GIP or glucose similar to those seen after oral glucose. The effect of 40 g i.v. glucose with three times the original dose of GIP was also investigated. No significant enhancement of glucose-stimulated insulin secretion was seen when GIP was infused with 10 or 20 g i.v. glucose; however, with 40 g a doubling of the insulin response occurred. The higher dose of GIP caused a further increase in insulin response (30-min increment, 972 +/- 191 pmol/L; compared with glucose alone, 356 +/- 100 pmol/L, P less than 0.01; and compared with low GIP, 602 +/- 247 pmol/L, P less than 0.02). The glucose increment after the 40-g i.v. dose was +9.2 mmol/L. The concentration of GIP and glucose required to produce significant potentiation of the insulin response appears to be in the pharmacologic, rather than physiologic, range.
葡萄糖依赖性促胰岛素多肽（GIP）据说是增强胰岛素对口服葡萄糖反应的主要生理因素。然而，GIP是否在葡萄糖或GIP的生理浓度下促进胰岛素释放仍存在疑问。为了进一步研究这一点，给志愿者静脉输注10、20或40克葡萄糖，同时或不同时输注GIP，以使血浆中GIP或葡萄糖水平与口服葡萄糖后所见水平相似。还研究了40克静脉注射葡萄糖与三倍原始剂量GIP的效果。当GIP与10或20克静脉注射葡萄糖一起输注时，未观察到葡萄糖刺激的胰岛素分泌有显著增强；然而，当输注40克时，胰岛素反应增加了一倍。更高剂量的GIP导致胰岛素反应进一步增加（30分钟增量，972±191 pmol/L；与单独使用葡萄糖相比，为356±100 pmol/L，P＜0.01；与低剂量GIP相比，为602±247 pmol/L，P＜0.02）。40克静脉注射剂量后的葡萄糖增量为+9.2 mmol/L。产生胰岛素反应显著增强所需的GIP和葡萄糖浓度似乎处于药理范围而非生理范围。
