运动能迅速增加肌肉中葡萄糖转运体的表达、葡萄糖转运能力和肌肉中胰岛素刺激的糖原储存

Exercise induces rapid increases in GLUT4 expression, glucose transport capacity, and insulin-stimulated glycogen storage in muscle

 

研究机构:华盛顿大学医学院

文摘

骨骼肌中葡萄糖转运体(GLUT4)含量与葡萄糖转运能力密切相关。

 

在这项研究中,我们检验了这样一种假设,即肌肉对运动的早期适应性反应中,葡萄糖转运体的表达会迅速增加,从而增强糖原的储存。通过游泳锻炼的大鼠在长时间的锻炼后,在肌肉中显示出的GLUT4 mRNA增加了大约2倍,而肌肉中的葡萄糖转运蛋白表达量增加了50%

 

经过第二天的锻炼,肌肉中的葡萄糖转运体(GLUT4)进一步增加大约2倍,葡萄糖转运体mRNA没有增加。肌肉己糖激酶的活性在两天的运动后也增加了一倍。胰岛素、肌肉收缩或缺氧对葡萄糖转运活动的最大刺激与外延肌肉中葡萄糖转运体的适应性增加大致成比例。

 

在亚细胞肌肉分馏前使用胰岛素治疗,使两天游泳者的血浆膜分数的葡萄糖转运蛋白含量比对照组增加大约2倍。当长柄肌肉与葡萄糖和胰岛素一起孵育时,2天游泳者3小时的糖原积累量是对照组的两倍。

 

我们的结果表明,快速增加的葡萄糖转运体(GLUT4)表达是肌肉对锻炼的早期适应性反应。这种适应似乎是由翻译前机制介导的。我们假设这种适应的生理作用是增强肌肉糖原储存的补充。

 

 

Exercise induces rapid increases in GLUT4 expression, glucose transport capacity, and insulin-stimulated glycogen storage in muscle.

J M Ren, C F Semenkovich, E A Gulve, J Gao and J O Holloszy

+ Author Affiliations

 

Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.

Abstract

 

GLUT4 glucose transporter content and glucose transport capacity are closely correlated in skeletal muscle. In this study, we tested the hypothesis that a rapid increase in GLUT4 expression occurs as part of the early adaptive response of muscle to exercise and serves to enhance glycogen storage. Rats exercised by swimming had a approximately 2-fold increase in GLUT4 mRNA and a 50% increase in GLUT4 protein expression in epitrochlearis muscle 16 h after one prolonged exercise session. After a 2nd day of exercise, muscle GLUT4 protein was increased further to approximately 2-fold while there was no additional increase in GLUT4 mRNA. Muscle hexokinase activity also doubled in response to 2 days of exercise. Glucose transport activity maximally stimulated with insulin, contractions, or hypoxia was increased roughly in proportion to the adaptive increase in GLUT4 protein in epitrochlearis muscles. Treatment with insulin prior to subcellular fractionation of muscle resulted in a approximately 2-fold greater increase in GLUT4 content of a plasma membrane fraction in the 2-day swimmers than in controls. When epitrochlearis muscles were incubated with glucose and insulin, glycogen accumulation over 3 h was twice as great in muscles from 2-day swimmers as in control muscles. Our results show that a rapid increase in GLUT4 expression is an early adaptive response of muscle to exercise. This adaptation appears to be mediated by pretranslational mechanisms. We hypothesize that the physiological role of this adaptation is to enhance replenishment of muscle glycogen stores.

 

http://www.jbc.org/content/269/20/14396.abstract