Characterization of glucose transporters in skeletal muscle after acclimatization to hypobaric hypoxia
Characterization of glucose transporters in skeletal muscle after acclimatization to hypobaric hypoxia
复制标题
DOI：
--
复制
发表时间：
2004
期刊：
影响因子：
--
通讯作者：
H. Qing
中科院分区：
文献类型：
--
作者：
H. Qing
目的探讨低压低氧习服过程中骨骼肌葡萄糖摄取变化的机制。方法将Wistar大鼠置于模拟海拔5000m的低压缺氧舱中，每天23h，连续30d。对照组的大鼠留在舱外。在低压低氧舱中采集两组动物的动脉血和后肢骨骼肌。用3H D葡萄糖测定骨骼肌葡萄糖摄取率（GUR）。骨骼肌的细胞内膜和质膜通过不连续糖梯度（25%、35%）分离。Scatchard法测定膜上葡萄糖转运蛋白的最大结合位点（Bmax）和Kd值。分别采用Western blotting和RT PCR检测骨骼肌膜GLUT 1和GLUT 4蛋白和mRNA的表达。结果与对照组相比，缺氧组大鼠骨骼肌葡萄糖水平明显升高。低氧组大鼠骨骼肌GUR高于对照组。低氧组大鼠骨骼肌细胞质膜和细胞内膜上葡萄糖转运蛋白的Bmax较对照组增加，但葡萄糖转运蛋白的Kd在低氧习服过程中无明显变化。低氧组大鼠骨骼肌细胞膜GLUT1、GLUT4表达均高于对照组。结论低压低氧习服后，骨骼肌细胞质膜和细胞内膜GLUT4和GLUT1的表达增加，可能在骨骼肌葡萄糖摄取增加中起重要作用。
Objective To explore the mechanism of changes of glucose uptaking in the skeletal muscle during acclimatization to hypobaric hypoxia. Methods Wistar rats in the hypoxia group were exposed to hypobaric hypoxia chamber simulating 5 000 m high altitude for 30 d (23 h per day). Rats in the control group stayed outside of the chamber. The arterial blood and the skeletal muscle from the hind leg were collected from animals in both groups in the hypobaric hypoxic chamber. 3H D glucose was used to assay the glucose uptake rate (GUR) in the skeletal muscle. The intracellular and plasma membranes of the skeletal muscle were separated by discontinuous sugar gradient (25%, 35%). The maximal binding sites (Bmax) and Kd of glucose transporters on the membranes were analyzed by Scatchard. The expression of protein and mRNA of GLUT1 and GLUT4 in the skeletal muscle membrane were detected by Western blotting and RT PCR, respectively. Results Compared with that in the control group, the glucose level in the skeletal muscle of rats in the hypoxic group increased significantly. GUR in the skeletal muscle in rats in the hypoxic group was higher than that in the control group. Bmax of glucose transporters on the skeletal muscle cell plasma and intracellular membranes in rats in the hypoxia group increased as compared with that in rats in the control group, but no significant change of Kd of the glucose transporters was found during acclimatization to hypoxia. Expressions of GLUT1 and GLUT4 in the skeletal muscle plasma membrane in rats in the hypoxic group were higher than those in rats in the control group. The level of GLUT4 mRNA increased in hypoxia, but no significant change of GLUT1was found. Conclusion After acclimatization to hypobaric hypoxia, increased GLUT4 and GLUT1 expressions are found in the skeletal muscle plasma membranes and intracellular membranes, which may play an important role in the increase of glucose uptake.