Bernard J R, Crain A M, Rivas D A, Herr H J, Reeder D W, Yaspelkis B B
Exercise Biochemistry Laboratory, Department of Kinesiology, College of Health and Human Development, California State University Northridge, 91330-8287, USA.
Acta Physiol Scand. 2005 Apr;183(4):357-66. doi: 10.1111/j.1365-201X.2005.01408.x.
The aim of this study was to provide a more extensive evaluation of the effects of chronic aerobic exercise on various components of the insulin signalling cascade in normal rodent skeletal muscle because of the limited body of literature that exists in this area of investigation.
Male Sprague-Dawley rats were assigned to either control (n = 7) or chronic aerobic exercise (n = 7) groups. Aerobic exercise animals were run 3 day week(1) for 45 min on a motor-driven treadmill (32 m min(1), 15% grade) for a 12 week period. Following the training period, all animals were subjected to hind limb perfusion in the presence of 500 microU mL(1) insulin to determine what effect chronic aerobic training had on various components of the insulin signalling cascade, c-Cbl protein concentration and c-Cbl phosphorylation.
Twelve weeks of aerobic training did not alter skeletal muscle Akt 1/2 protein concentration, Akt Ser 473 phosphorylation, Akt Thr 308 phosphorylation, Akt 1 activity, aPKC-zeta protein concentration, aPKC-lambda protein concentration or c-Cbl protein concentration. In contrast, chronic aerobic exercise increased insulin-stimulated phosphatidylinositol 3-kinase, Akt 2 kinase and aPKC-zeta/lambda kinase activities, as well as c-Cbl tyrosine phosphorylation, in a fibre type specific response to aerobic training. In addition, chronic aerobic exercise enhanced insulin-stimulated plasma membrane glucose transporter 4 (GLUT4) protein concentration.
Collectively, these findings suggest that chronic aerobic exercise enhances components of both the classical and novel insulin signalling cascades in normal rodent skeletal muscle, which may contribute to an increased insulin-stimulated plasma membrane GLUT4 protein concentration.
由于该研究领域现有文献有限，本研究旨在更全面地评估慢性有氧运动对正常啮齿动物骨骼肌中胰岛素信号级联反应各组分的影响。
将雄性Sprague-Dawley大鼠分为对照组（n = 7）和慢性有氧运动组（n = 7）。有氧运动组动物每周3天在电动跑步机上以32米/分钟的速度、15%的坡度跑45分钟，持续12周。训练期结束后，所有动物在500微单位/毫升胰岛素存在的情况下进行后肢灌注，以确定慢性有氧运动对胰岛素信号级联反应各组分、c-Cbl蛋白浓度和c-Cbl磷酸化的影响。
12周的有氧运动并未改变骨骼肌中Akt 1/2蛋白浓度、Akt丝氨酸473磷酸化、Akt苏氨酸308磷酸化、Akt 1活性、非典型蛋白激酶C-ζ蛋白浓度、非典型蛋白激酶C-λ蛋白浓度或c-Cbl蛋白浓度。相比之下，慢性有氧运动以对有氧训练的纤维类型特异性反应增加了胰岛素刺激的磷脂酰肌醇3激酶、Akt 2激酶和非典型蛋白激酶C-ζ/λ激酶活性，以及c-Cbl酪氨酸磷酸化。此外，慢性有氧运动增强了胰岛素刺激的质膜葡萄糖转运蛋白4（GLUT4）蛋白浓度。
总体而言，这些发现表明慢性有氧运动增强了正常啮齿动物骨骼肌中经典和新型胰岛素信号级联反应的组分，这可能有助于增加胰岛素刺激的质膜GLUT4蛋白浓度。
