Greco-Perotto R, Zaninetti D, Assimacopoulos-Jeannet F, Bobbioni E, Jeanrenaud B
J Biol Chem. 1987 Jun 5;262(16):7732-6.
The effect of cold adaptation (4 degrees C) on the in vivo glucose utilization and on the number and properties of the glucose transporters has been studied in brown adipose tissue of normal rats. Glucose utilization was assessed in vivo by the 2-deoxyglucose method. Glucose transporters in plasma and microsomal membranes were quantified by the [3H]cytochalasin B-binding assay. After cold adaptation the in vivo glucose utilization by brown adipose tissue increased 21-fold compared to controls (22 degrees C). The number of glucose transporters in plasma membranes of brown adipose tissue increased from 75 to 436 pmol/g tissue and that of total glucose transporters (plasma + microsomal membranes) from 438 to 754 pmol/g tissue. In addition, cold adaptation increased the Hill coefficient of the plasma membrane transporter for cytochalasin B from 0.90 to 2.03 and decreased the Kd from 100 to 54 nM. This study shows that cold adaptation promotes: a translocation of glucose transporters from an intracellular pool to plasma membranes; an increased number of plasma membrane glucose transporters unaccounted for by the translocation process (e.g. "de novo" synthesis); an increase in the Hill coefficient for cytochalasin B that could also represent changes in the properties of the transporters vis-à-vis glucose, (e.g. positive cooperativity); and a decrease in the Kd value for cytochalasin B.
在正常大鼠的棕色脂肪组织中，研究了冷适应（4摄氏度）对体内葡萄糖利用以及葡萄糖转运体数量和特性的影响。采用2-脱氧葡萄糖法在体内评估葡萄糖利用情况。通过[3H]细胞松弛素B结合试验对质膜和微粒体膜中的葡萄糖转运体进行定量。冷适应后，棕色脂肪组织的体内葡萄糖利用量与对照组（22摄氏度）相比增加了21倍。棕色脂肪组织质膜中葡萄糖转运体的数量从75皮摩尔/克组织增加到436皮摩尔/克组织，总葡萄糖转运体（质膜 + 微粒体膜）的数量从438皮摩尔/克组织增加到754皮摩尔/克组织。此外，冷适应使质膜转运体对细胞松弛素B的希尔系数从0.90增加到2.03，并使解离常数从100纳摩尔降低到54纳摩尔。本研究表明，冷适应促进：葡萄糖转运体从细胞内池转运到质膜；质膜葡萄糖转运体数量增加，而这一增加无法用转运过程来解释（例如“从头”合成）；细胞松弛素B的希尔系数增加，这也可能代表转运体相对于葡萄糖的特性发生了变化（例如正协同性）；以及细胞松弛素B的解离常数降低。
