Coleto R, Bolufer J, Vazquez C M
Dpto. Fisiología y Biología Animal, Facultad de Farmacia, Universidad de Sevilla, Spain.
Poult Sci. 1998 Apr;77(4):594-9. doi: 10.1093/ps/77.4.594.
Taurocholate transport was studied in brush border membrane vesicles (BBMV) isolated from chicken small (duodenum, jejunum, and ileum) and large (proximal cecum and rectum) intestines, using a rapid filtration technique. The purity of the BBMV was verified by the finding that the specific activity of sucrase (a brush border membrane enzyme marker) was severalfold greater in vesicles than corresponding values in mucosal homogenate. The functional integrity of isolated BBMV was evaluated by the uptake of D-glucose, which showed a transient increase in the presence of Na+. A Na+-dependence of taurocholate uptake was shown in BBMV prepared from ileum, cecum, and rectum, as taurocholate transport was transiently increased (accumulation) in the presence of a Na+ gradient between the external medium and intravesicular medium. The magnitude of the accumulation was similar among ileum, cecum, and rectum. In contrast, BBMV prepared from duodenum and jejunum did not show any Na+-dependent taurocholate transport, as the taurocholate uptake was not affected when a Na+ gradient was replaced by a K+ gradient. The use of taurochenodeoxycholate in the incubation medium inhibited Na+-dependent taurocholate transport in the ileum, cecum, and rectum. This study is the first to show the presence of a Na+-dependent bile salt transport in BBMV obtained from chicken ileum, proximal cecum, and rectum.
采用快速过滤技术，对从鸡的小肠（十二指肠、空肠和回肠）和大肠（近端盲肠和直肠）分离出的刷状缘膜囊泡（BBMV）中的牛磺胆酸盐转运进行了研究。通过发现蔗糖酶（一种刷状缘膜酶标志物）的比活性在囊泡中比在粘膜匀浆中的相应值高几倍，验证了BBMV的纯度。通过D-葡萄糖的摄取评估分离的BBMV的功能完整性，在Na+存在下其显示出短暂增加。在从回肠、盲肠和直肠制备的BBMV中显示出牛磺胆酸盐摄取对Na+的依赖性，因为在外部介质和囊泡内介质之间存在Na+梯度时，牛磺胆酸盐转运短暂增加（积累）。回肠、盲肠和直肠之间积累的程度相似。相比之下，从十二指肠和空肠制备的BBMV未显示任何Na+依赖性牛磺胆酸盐转运，因为当Na+梯度被K+梯度取代时，牛磺胆酸盐摄取不受影响。在孵育培养基中使用牛磺鹅去氧胆酸盐抑制了回肠、盲肠和直肠中Na+依赖性牛磺胆酸盐转运。本研究首次表明，从鸡回肠、近端盲肠和直肠获得的BBMV中存在Na+依赖性胆盐转运。
