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 w as 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 w ere 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 GLUT 4 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 GLUT 4 concentration and CS activity were not changed as compared with the control muscle. These data could be interpreted that GLUT 4 concentration and mitochondrial oxidative enzyme activity in skeletal muscle are coregulated.
|ジャーナル||Japanese Journal of Physical Fitness and Sports Medicine|
|出版ステータス||Published - 1993|
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