局所的な筋活動量の変動による骨格筋糖輸送体濃度の変化

概要

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In the present study, we examined whether GLUT4 concentration in rat skeletal muscle is dependent on local muscle activity level or not. In ten male Sprague-Dawley rats, one side of gastrocnemius muscle was tenotomized, and the other side contralateral muscle was treated sham operation as a control. Gastrocnemius and plantaris muscles were excised from both legs at the five weeks after surgery. After the muscles were weighed, GLUT 4 concentration and citrate synthase(CS)activity were measured. The results are summarized as follows:In gastrocnemius muscle, tenotomy induced decreases of 25% in muscle weight, 16% in CS activity, and 25% in GLUT4 concentration as compared with the control muscle. These data suggest that although extramuscular environment is similar, different GLUT 4 concentration in both muscles is induced by different muscle activity level. Therefore, it is concluded that muscle activity level regulates GLUT 4 concentration in skeletal muscle. In overloaded synergistic plantaris muscle, muscle weight and GLUT 4 content per whole muscle were increased by 18% and 17%, respectively, but GLUT4 concentration and CS activity were not changed as compared with the control muscle. These data could be interpreted that GLUT4 concentration and mitochondrial oxidative enzyme activity in skeletal muscle are coregulated.
1993-08-01