Bradford N M, McGivan J D
Biochim Biophys Acta. 1982 Jul 14;689(1):55-62. doi: 10.1016/0005-2736(82)90188-2.
(1) The transport of alanine and glutamine into isolated rat intestinal epithelial cells, prepared as described previously (Watford, M., Lund, P. and Krebs, H.A. (1979) Biochem. J. 178, 589-596), was studied. (2) Cells isolated by this method accumulated alanine 7-fold from an external concentration of 0.5 mM, and by this criterion appear more suitable for transport studies than do previous rat intestinal cell preparations. (3) In these cells, it was shown using several different approaches that the major part of the transport of alanine and glutamine is mediated by a common carrier which is Na+ dependent and is sensitive to inhibition by 2-methylaminoisobutyric acid. (4) These results are in contrast to the situation in isolated hepatocytes were glutamine is transported by a carrier system (System N) distinct from that that which mediates the transport of alanine. (5) It is suggested that a major metabolic function of this transport system in intestinal cells is the exchange of extracellular glutamine for intracellular alanine, which is a major product of glutamine metabolism in the gut.
（1）研究了丙氨酸和谷氨酰胺进入如前所述制备的（沃特福德，M.，伦德，P.和克雷布斯，H.A.（1979年）《生物化学杂志》178卷，589 - 596页）分离的大鼠肠上皮细胞的转运情况。（2）用这种方法分离的细胞从外部浓度为0.5 mM的溶液中积累丙氨酸的量达7倍，据此标准，它们似乎比以前的大鼠肠细胞制剂更适合用于转运研究。（3）在这些细胞中，使用几种不同方法表明，丙氨酸和谷氨酰胺转运的主要部分是由一种共同载体介导的，该载体依赖Na +，并对2 - 甲基氨基异丁酸的抑制敏感。（4）这些结果与分离的肝细胞中的情况形成对比，在肝细胞中谷氨酰胺是由一个与介导丙氨酸转运的载体系统（系统N）不同的载体系统转运的。（5）有人提出，该转运系统在肠细胞中的一个主要代谢功能是细胞外谷氨酰胺与细胞内丙氨酸的交换，丙氨酸是肠道中谷氨酰胺代谢的主要产物。
