Department of Pathology and Laboratory Medicine, Genome Research Institute, University of Cincinnati, 2180 E. Galbraith Road, Cincinnati, OH 45237, USA.
Obes Surg. 2010 Jun;20(6):768-75. doi: 10.1007/s11695-010-0095-1. Epub 2010 Feb 23.
Enteroendocrine K cells secrete the incretin hormone glucose-dependent insulinotropic peptide (GIP) and are predominately located in the duodenum. GIP levels should decrease after gastric bypass due to duodenal exclusion; however, studies have found conflicting data regarding the changes in GIP secretion after gastric bypass and duodenal-jejunal bypass (DJB).
We performed a DJB or Sham surgery on Wistar rats followed by an oral glucose tolerance test on postoperative (post-op) day 12 and superior mesenteric lymphatic cannulation on post-op day 14. We measured meal-stimulated GIP concentrations and small bowel GIP and GLP-1 protein content after DJB or Sham surgery.
There was no difference in glucose tolerance by 12 days post-op. We found no difference in lymphatic GIP concentration area under the curve between DJB and Sham rats (15,240 pg/ml min +/- 2,651 vs. 17,201 pg/ml min +/- 2,763, respectively, p = 0.62). GIP and GLP-1 protein contents were both significantly increased only in the midjejunum in DJB rats compared to Sham rats (p = 0.009 and p = 0.01, respectively).
Plasma and lymphatic GIP concentrations did not significantly change after DJB in Wistar rats. DJB increased GIP protein content in the midjejunum at the new site of nutrient absorption, but this was surprisingly not countered by a decrease in GIP protein content in the bypassed duodenum. Further studies are needed to determine the mechanisms that account for the discrepancy in GIP production and subsequent secretion after DJB as well as what role GIP plays in the effect of gastrointestinal surgery on glucose homeostasis.
肠内分泌 K 细胞分泌肠促胰岛素激素葡萄糖依赖性胰岛素促分泌肽（GIP），主要位于十二指肠。胃旁路术后由于十二指肠排除，GIP 水平应该降低；然而，关于胃旁路和十二指肠空肠旁路（DJB）后 GIP 分泌的变化，研究结果存在矛盾。
我们对 Wistar 大鼠进行 DJB 或假手术，然后在术后第 12 天进行口服葡萄糖耐量试验，在术后第 14 天进行肠系膜淋巴导管插管。我们测量了 DJB 或假手术后进食刺激的 GIP 浓度以及小肠 GIP 和 GLP-1 蛋白含量。
术后 12 天，葡萄糖耐量没有差异。我们发现 DJB 和假手术大鼠的淋巴 GIP 浓度曲线下面积没有差异（15,240 pg/ml min +/- 2,651 与 17,201 pg/ml min +/- 2,763，分别，p = 0.62）。与假手术大鼠相比，只有 DJB 大鼠的中肠 GIP 和 GLP-1 蛋白含量均显著增加（分别为 p = 0.009 和 p = 0.01）。
在 Wistar 大鼠中，DJB 后血浆和淋巴 GIP 浓度没有显著变化。DJB 增加了新的营养吸收部位中肠的 GIP 蛋白含量，但这并没有被绕过的十二指肠中 GIP 蛋白含量的减少所抵消。需要进一步研究以确定 DJB 后 GIP 产生和随后分泌的差异的机制，以及 GIP 在胃肠手术对葡萄糖稳态的影响中的作用。
