Department of Physiology, University of Veterinary Medicine Hannover, Foundation, 30173 Hannover, Germany.
Comp Biochem Physiol A Mol Integr Physiol. 2012 Sep;163(1):161-9. doi: 10.1016/j.cbpa.2012.05.204. Epub 2012 Jun 7.
It has been shown in several species that the intestinal Na(+)-dependent glucose co-transporter 1 (SGLT1) is more abundant in the jejunum than in ileum. In contrast, the efficiency of intestinal glucose uptake rates in suckling piglets or weaned pigs is not clearly fitting with this segmental distribution. The aim of this study was to evaluate SGLT1 mediated glucose absorption in the jejunum and ileum of growing pigs (Sus scrofa) in more detail. In Ussing chambers, basal short-circuit currents were significantly more positive in the jejunum. It could be demonstrated that the electrogenic ileal glucose transport was significantly more pronounced in different breeds and occurred at 5 mmol∙L(-1) glucose 7 times faster in the ileum, although slightly higher jejunal expression of glycosylated SGLT1 was detected by Western blotting. This expression pattern was connected to significantly lower phlorizin sensitivity in the jejunum. As the more efficient ileal glucose absorption was also observable with glucose uptake studies into isolated brush-border membrane vesicles without differences in abundance and activity of the Na(+)/K(+)-ATPase in both segments, we conclude that the segmental differences in porcine glucose transport characteristics may be based on direct or indirect modulations of SGLT1 activity.
已有研究表明，在多种物种中，肠道钠依赖葡萄糖协同转运蛋白 1（SGLT1）在空肠中的含量高于回肠。然而，在哺乳仔猪或断奶仔猪中，肠道葡萄糖摄取率的效率并不完全符合这种节段性分布。本研究旨在更详细地评估生长猪（Sus scrofa）空肠和回肠中 SGLT1 介导的葡萄糖吸收。在 Ussing 室中，空肠的基础短路电流明显更为正。研究结果表明，电活性回肠葡萄糖转运在不同品种中更为明显，并且在 5mmol·L(-1)葡萄糖时，回肠中的葡萄糖转运速度快 7 倍，尽管通过 Western blot 检测到空肠中糖基化 SGLT1 的表达略有升高。这种表达模式与空肠中明显较低的梓醇敏感性有关。由于在没有 Na(+)/K(+)-ATPase 丰度和活性差异的情况下，用分离的刷状缘膜囊进行的葡萄糖摄取研究也可以观察到回肠中葡萄糖吸收效率更高，因此我们得出结论，猪葡萄糖转运特性的节段性差异可能基于 SGLT1 活性的直接或间接调节。
