Kühl C, Hornnes P J, Jensen S L, Lauritsen K B
Endocrinology. 1980 Nov;107(5):1446-50. doi: 10.1210/endo-107-5-1446.
The responses of gastric inhibitory polypeptide (GIP) and insulin to intraduodenal (OGTT) and iv (IVGI) glucose infusions were measured in 14 late fetal and 9 neonatal pigs. Basal plasma glucose (P < 0.01) and GIP (P < 0.001) concentrations were lower in the fetal than in the neonatal pigs, while basal plasma insulin was not significantly different in the two groups. In the fetal pigs, almost identical plasma glucose curves were obtained during the OGTT and the IVGI, but plasma insulin did not change during either test. In these pigs, plasma GIP increased 3-fold (P < 0.01) during the OGTT, whereas no significant changes in plasma GIP were observed during the IVGI. In the neonatal pigs, plasma glucose increased more during the OGTT than during the IVGI, but plasma insulin exhibited similar increments during both tests. Thus, the insulinogenic index of the IVGI was almost 3 times higher than that of the OGTT (P < 0.05). In contrast to the normal increment in plasma GIP observed in fetal pigs, plasma GIP decreased significantly during both tests in the neonatal pigs. It is concluded that beta-cells of fetal pigs are unresponsive to acute elevations of plasma glucose with or without a concomitant increase in plasma GIP. Conversely, beta-cells of neonatal pigs exhibit a significant response to hyperglycemia, but the enteroinsular axis is defective, since more insulin is released after iv than during intraduodenal glucose administration. The defective enteroinsular axis in neonatal pigs might be due to the observed fall in plasma GIP during the OGTT.
在14头晚期胎儿猪和9头新生猪中测量了胃抑制多肽（GIP）和胰岛素对十二指肠内（口服葡萄糖耐量试验，OGTT）和静脉内（静脉葡萄糖耐量试验，IVGI）输注葡萄糖的反应。胎儿猪的基础血浆葡萄糖（P<0.01）和GIP（P<0.001）浓度低于新生猪，而两组的基础血浆胰岛素无显著差异。在胎儿猪中，OGTT和IVGI期间获得的血浆葡萄糖曲线几乎相同，但两项试验期间血浆胰岛素均未变化。在这些猪中，OGTT期间血浆GIP增加了3倍（P<0.01），而IVGI期间血浆GIP未观察到显著变化。在新生猪中，OGTT期间血浆葡萄糖的升高幅度大于IVGI，但两项试验期间血浆胰岛素的升高幅度相似。因此，IVGI的胰岛素生成指数几乎是OGTT的3倍（P<0.05）。与胎儿猪中观察到的血浆GIP正常升高相反，新生猪在两项试验期间血浆GIP均显著下降。结论是，胎儿猪的β细胞对血浆葡萄糖的急性升高无反应，无论是否伴有血浆GIP的增加。相反，新生猪的β细胞对高血糖有显著反应，但肠胰岛轴存在缺陷，因为静脉注射葡萄糖后释放的胰岛素比十二指肠内注射葡萄糖时更多。新生猪肠胰岛轴的缺陷可能是由于OGTT期间观察到的血浆GIP下降所致。
