Wheeler T J, Fell R D, Hauck M A
Department of Biochemistry, University of Louisville, KY 40292.
Biochim Biophys Acta. 1994 Dec 30;1196(2):191-200. doi: 10.1016/0005-2736(94)00211-8.
Our previous studies on the acute regulation of glucose transport in perfused rat hearts were extended to explore further the mechanism of regulation by anoxia; to test the effects of palmitate, a transport inhibitor; and to compare the translocation of two glucose transporter isoforms (GLUT1 and GLUT4). Following heart perfusions under various conditions, glucose transporters in intracellular membranes were quantitated by reconstitution of transport activity and by Western blotting. Rotenone stimulated glucose uptake and decreased the intracellular contents of glucose transporters. This indicates that it activates glucose transport via net outward translocation, similarly to anoxia. However, two uncouplers of oxidative phosphorylation produced little or no effect. Increased workload (which stimulates glucose transport) reduced the intracellular contents of transporters, while palmitate increased the contents, indicating that these factors cause net translocation from or to the intracellular pool, respectively. Relative changes in GLUT1 were similar to those in GLUT4 for most factors tested. A plot of changes in total intracellular transporter content vs. changes in glucose uptake was roughly linear, with a slope of -0.18. This indicates that translocation accounts for most of the changes in glucose transport, and the basal pool of intracellular transporters is five times as large as the plasma membrane pool.
我们之前关于灌注大鼠心脏中葡萄糖转运急性调节的研究得以拓展，进一步探究缺氧调节机制；测试转运抑制剂棕榈酸酯的作用；并比较两种葡萄糖转运体亚型（GLUT1和GLUT4）的转位情况。在各种条件下进行心脏灌注后，通过转运活性重建和蛋白质免疫印迹法对细胞内膜中的葡萄糖转运体进行定量。鱼藤酮刺激葡萄糖摄取并降低葡萄糖转运体的细胞内含量。这表明它与缺氧类似，通过净外向转位激活葡萄糖转运。然而，两种氧化磷酸化解偶联剂几乎没有产生影响。增加工作负荷（刺激葡萄糖转运）会降低转运体的细胞内含量，而棕榈酸酯则会增加其含量，表明这些因素分别导致从细胞内池的净转位或向细胞内池的净转位。对于大多数测试因素，GLUT1的相对变化与GLUT4相似。细胞内转运体总含量变化与葡萄糖摄取变化的关系图大致呈线性，斜率为 -0.18。这表明转位是葡萄糖转运变化的主要原因，细胞内转运体的基础池是质膜池的五倍大。
