Schoeller C, Keelan M, Mulvey G, Stremmel W, Thomson A B
Division of Gastroenterology, University of Alberta, Edmonton, Canada.
Biochim Biophys Acta. 1995 May 24;1236(1):51-64. doi: 10.1016/0005-2736(95)00035-2.
Oleic acid uptake was studied using adult rabbit and rat jejunal brush border membrane vesicles. There was a reduction of oleic acid uptake following trypsin-treatment. Opposing Na+/H+ gradients (inward Na+ and outward H+ gradients) increased oleic acid uptake by about 40%, as compared with only an inward Na+ gradient, only an outward H+ gradient, or the absence of either Na+ or H+ gradients. The addition of mucin further increased the enhanced uptake of oleic acid observed in the presence of opposing Na+/H+ gradients. Amiloride, an inhibitor of the Na+/H+ exchanger, reduced by about 40% the uptake of oleic acid into sheets of rat jejunum, and this inhibitory effect was observed over a range of rates of stirring of the bulk phase. In rabbit jejunal brush border membrane vesicles, amiloride reduced oleic acid uptake in the presence but not in the absence of opposing Na+/H+ gradients, with a Ki of approx. 36 microM. Thus, oleic acid uptake occurs largely by partitioning of the lipid into the brush border membrane, influenced by a process which involves the activation of the brush border membrane Na+/H+ exchanger.
使用成年兔和大鼠空肠刷状缘膜囊泡研究油酸摄取。胰蛋白酶处理后油酸摄取减少。与仅存在内向Na⁺梯度、仅存在外向H⁺梯度或不存在Na⁺或H⁺梯度相比，相反的Na⁺/H⁺梯度（内向Na⁺和外向H⁺梯度）使油酸摄取增加约40%。添加粘蛋白进一步增加了在相反Na⁺/H⁺梯度存在下观察到的油酸摄取增强。氨氯地平，一种Na⁺/H⁺交换体抑制剂，使大鼠空肠片对油酸的摄取减少约40%，并且在本体相的一系列搅拌速率下均观察到这种抑制作用。在兔空肠刷状缘膜囊泡中，氨氯地平在存在相反Na⁺/H⁺梯度时降低油酸摄取，但在不存在时则无此作用，其抑制常数（Ki）约为36微摩尔。因此，油酸摄取主要通过脂质分配到刷状缘膜中发生，这一过程受涉及刷状缘膜Na⁺/H⁺交换体激活的过程影响。
