Kainulainen H, Komulainen J, Joost H G, Vihko V
Department of Clinical Medicine, University of Tampere, Finland.
Pflugers Arch. 1994 Jul;427(5-6):444-9. doi: 10.1007/BF00374259.
The effects of long-term, moderate physical exercise on in vivo glucose uptake, levels of two glucose transporter proteins (GLUT1 and GLUT4) and activities of various key enzymes of energy metabolism were measured in skeletal muscle from streptozotocin-diabetic rats. Diabetes (12-16 weeks) reduced the in vivo glucose uptake (glucose metabolic index, GMI) in muscle containing mainly type I fibres by 55% but had no effect in muscles containing mainly type IIa and IIb fibres. GMI was increased in the diabetic white skeletal muscle (mainly type IIb fibres) by more than 120%. In contrast to the complex changes in GMI, GLUT4 levels were reduced in all types of skeletal muscle from diabetic rats with no change in GLUT1 levels. Exercise training had no effects on GMI or the glucose transporter levels. Streptozotocin induced diabetes significantly reduced the oxidative capacity of skeletal muscle assayed as the activities of citrate synthase, succinate dehydrogenase and cytochrome c oxidase. Training increased the activities of oxidative enzymes, with this increase being more prominent in the diabetic animals. The present data indicate that long-term streptozotocin-induced diabetes decreases oxidative metabolic capacity and GLUT4 protein levels in skeletal muscle, but that the changes of glucose transport largely depend on the fibre type composition. Moderate training fully reverses the effect of insulinopenia and hyperglycaemia on muscle oxidative metabolism. In contrast to the previous suggestions, the expression of GLUT4 is not correlated with the capacity of oxidative metabolism in skeletal muscle of streptozotocin-diabetic rats.
在链脲佐菌素诱导的糖尿病大鼠的骨骼肌中，测定了长期适度体育锻炼对体内葡萄糖摄取、两种葡萄糖转运蛋白（GLUT1和GLUT4）水平以及能量代谢各种关键酶活性的影响。糖尿病（12 - 16周）使主要含I型纤维的肌肉中的体内葡萄糖摄取（葡萄糖代谢指数，GMI）降低了55%，但对主要含IIa和IIb型纤维的肌肉没有影响。糖尿病白色骨骼肌（主要为IIb型纤维）中的GMI增加了120%以上。与GMI的复杂变化相反，糖尿病大鼠所有类型骨骼肌中的GLUT4水平均降低，而GLUT1水平没有变化。运动训练对GMI或葡萄糖转运蛋白水平没有影响。链脲佐菌素诱导的糖尿病显著降低了以柠檬酸合酶、琥珀酸脱氢酶和细胞色素c氧化酶活性测定的骨骼肌氧化能力。训练增加了氧化酶的活性，这种增加在糖尿病动物中更为显著。目前的数据表明，长期链脲佐菌素诱导的糖尿病会降低骨骼肌的氧化代谢能力和GLUT4蛋白水平，但葡萄糖转运的变化很大程度上取决于纤维类型组成。适度训练完全逆转了胰岛素缺乏和高血糖对肌肉氧化代谢的影响。与之前的观点相反，GLUT4的表达与链脲佐菌素诱导的糖尿病大鼠骨骼肌的氧化代谢能力无关。
