钠离子对仔猪小肠刷状缘膜囊二肽跨膜转运的影响

为研究Na 在仔猪小肠Gly-Pro跨膜转运中的作用,采用同位素示踪及体外孵育技术,观察在不同Na 浓度梯度条件下Gly-Pro在仔猪小肠刷状缘膜囊(brush border membrane vesicles,BBMV)的跨膜转运量。结果表明:(1)用K 替代Na ,并没有降低Gly-Pro在BBMV中的转运量,在孵育前20min时间内,Gly-Pro的转运量稍稍提高;(2)Na 可使BBMV对L-丙氨酸的转运量提高到4.6倍,但不影响Gly-Pro的转运;二氢骆驼蓬碱显著地降低L-丙氨酸的转运,但对Gly-Pro的转运无影响。研究提示,Gly-Pro在仔猪小肠BBMV体系中的转运与Na 不存在依赖性的关系。

Effects of Sodium Ion on Transport of Dipeptide in Small Intestinal Brush Border Membrane Vesicles of Piglets

In order to study the function of sodium ion in transmembrane transport of Gly-Pro dipeptide in small intestine of piglets, radioactive isotope trace and in vitro incubation technique were used to observe the transmembrane transport of Gly-Pro dipeptide in small intestinal brush border membrane vesicles (BBMV). The results showed that 1) transport of Gly-Pro was slightly quicker when Na replaced by K during the first period of 20 min; 2) Na concentration gradient stimulated 4.6-fold of L-alanine transport, but had no effect on transport of Gly-Pro. Harmaline reduced transoport of L-alanine significantly but had no effect on Gly-Pro transport. It was suggested that transport of dipeptide in small intestinal BBMV of piglets was independent on concentration gradient of Na .