Svensson A M, Efendic S, Ostenson C G, Jansson L
Department of Medical Cell Biology, Uppsala University, Sweden.
Peptides. 1997;18(7):1055-9. doi: 10.1016/s0196-9781(97)00031-4.
The aim of the study was to investigate how the incretin candidate hormone gastric inhibitory polypeptide (GIP) affects splanchnic blood flow, especially pancreatic islet blood flow. For this purpose, male Sprague-Dawley rats were injected intravenously with either saline or GIP (5 or 15 micrograms/kg body weight) 10 min before blood flow measurements by a microsphere technique. Furthermore, 3 min before the blood flow measurements, 1 ml of either saline or 30% D-glucose was given intravenously. All glucose-injected animals were markedly hyperglycemic (> 20 mmol/liter) at the time of the blood flow measurements. Both doses of GIP potentiated basal and glucose-stimulated insulin release. In the normoglycemic rats, the lowest dose of GIP did not affect the blood perfusion to any of the investigated organs. The highest dose of GIP decreased whole pancreatic and duodenal blood flow, whereas islet blood flow was unaffected. As a result, fractional islet blood flow was increased. In the hyperglycemic rats, where the islet blood flow was increased compared with control animals, both doses of GIP further enhanced islet blood flow. No effect on pancreatic, fractional islet, or duodenal blood flow was seen after GIP administration to hyperglycemic animals. It is concluded that administration of GIP can further augment the glucose-induced stimulation of islet blood flow. This may contribute to facilitating release of insulin from the islets.
本研究的目的是调查肠促胰岛素候选激素胃抑制多肽（GIP）如何影响内脏血流，尤其是胰岛血流。为此，在通过微球技术测量血流前10分钟，给雄性Sprague-Dawley大鼠静脉注射生理盐水或GIP（5或15微克/千克体重）。此外，在血流测量前3分钟，静脉注射1毫升生理盐水或30% D-葡萄糖。所有注射葡萄糖的动物在血流测量时均显著高血糖（>20毫摩尔/升）。两种剂量的GIP均增强基础和葡萄糖刺激的胰岛素释放。在血糖正常的大鼠中，最低剂量的GIP对任何被研究器官的血流灌注均无影响。最高剂量的GIP降低了整个胰腺和十二指肠的血流，而胰岛血流未受影响。结果，胰岛血流分数增加。在高血糖大鼠中，与对照动物相比胰岛血流增加，两种剂量的GIP均进一步增强了胰岛血流。给高血糖动物注射GIP后，对胰腺、胰岛血流分数或十二指肠血流均无影响。得出的结论是，GIP给药可进一步增强葡萄糖诱导的胰岛血流刺激。这可能有助于促进胰岛素从胰岛的释放。
