钠离子对仔猪小肠刷状缘膜囊二肽跨膜转运的影响(英文)

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

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。

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 transmem- brane 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^＋ .