Hainque B, Guerre-Millo M, Hainault I, Moustaid N, Wardzala L J, Lavau M
Unité de Recherches sur la Physiopathologie de la Nutrition, Institut National de la Santé et de la Recherche Médicale, U.177, Paris, France.
J Biol Chem. 1990 May 15;265(14):7982-6.
The question of a long term regulatory role of insulin on adipocyte glucose transporter content was addressed using the differentiating or fully mature 3T3-F442A adipocytes. Glucose transport was measured in intact cells. Glucose transporter content in plasma membranes and low density microsomes (LDM) was assessed by cytochalasin B binding and Western analysis. In insulin- versus spontaneously differentiated adipocytes, glucose transport and glucose transporters content of plasma membranes and LDM were increased 5-, 4-, and 2-fold, respectively. Insulin deprivation for 24 h induced a redistribution of glucose transporters in those cells which then displayed 2-fold higher glucose transport and glucose transporter content in plasma membranes than spontaneously differentiated cells and 3-fold more glucose transporters in LDM. When fully insulin-differentiated adipocytes were insulin-deprived for 4 days, there was a marked decrease in glucose transporters in both membrane fractions that was fully reversible by reexposing the cells to insulin for 4 days. Glucose uptake changes were closely proportionate to changes in glucose transporter content of plasma membranes as assessed by an antiserum to the C-terminal peptide of the erythrocyte/HepG2/brain-type glucose transporter. When Western blots were immunoblotted with 1F8 monoclonal antibody, specific for glucose transporter in insulin responsive tissues, an abundant immunoreactive protein was detected in both plasma membranes and LDM but the amount of this glucose transporter did not change with insulin exposure in any membrane fractions. In conclusion, insulin plays a long term regulatory role on cultured adipocyte glucose transporter content through a selective effect on the erythrocyte/HepG2/brain-type glucose transporter.
利用分化中的或完全成熟的3T3 - F442A脂肪细胞研究了胰岛素对脂肪细胞葡萄糖转运体含量的长期调节作用。在完整细胞中测量葡萄糖转运。通过细胞松弛素B结合和蛋白质免疫印迹分析评估质膜和低密度微粒体（LDM）中的葡萄糖转运体含量。与自发分化的脂肪细胞相比，胰岛素处理的脂肪细胞质膜和LDM中的葡萄糖转运和葡萄糖转运体含量分别增加了5倍、4倍和2倍。24小时的胰岛素剥夺诱导了这些细胞中葡萄糖转运体的重新分布，随后这些细胞的质膜中葡萄糖转运和葡萄糖转运体含量比自发分化的细胞高2倍，LDM中的葡萄糖转运体多3倍。当完全胰岛素分化的脂肪细胞被剥夺胰岛素4天时，两个膜组分中的葡萄糖转运体都显著减少，通过将细胞重新暴露于胰岛素4天，这种减少是完全可逆的。用针对红细胞/ HepG-2 /脑型葡萄糖转运体C末端肽的抗血清评估，葡萄糖摄取变化与质膜中葡萄糖转运体含量的变化密切相关。当用对胰岛素反应性组织中的葡萄糖转运体具有特异性的1F8单克隆抗体对蛋白质免疫印迹进行免疫印迹时，在质膜和LDM中均检测到丰富的免疫反应性蛋白，但这种葡萄糖转运体的量在任何膜组分中都不会随胰岛素暴露而改变。总之，胰岛素通过对红细胞/ HepG-2 /脑型葡萄糖转运体的选择性作用，对培养的脂肪细胞葡萄糖转运体含量发挥长期调节作用。
