Zhou Q, Dohm G L
Department of Biochemistry, East Carolina University School of Medicine, Greenville, North Carolina 27858, USA.
Biochem Biophys Res Commun. 1997 Jul 30;236(3):647-50. doi: 10.1006/bbrc.1997.7028.
Exercise has been shown to increase insulin-stimulated skeletal muscle glucose transport. Activation of phosphatidylinostol 3-kinase (PI 3-kinase) is required for insulin to stimulate glucose transport. The present study was designed to investigate whether treadmill running (60 min, 8% grade, 30 m/min) augments insulin-stimulated activation of PI 3-kinase. Insulin dramatically increased insulin receptor substrate-1 (IRS-1) tyrosine phosphorylation (p < 0.05). Treadmill running did not induce IRS-1 tyrosine phosphorylation, not did it alter insulin-stimulated IRS-1 tyrosine phosphorylation. Insulin increased PI 3-kinase activity by 3.0-fold (over basal activity) in white muscle and 5.2-fold in red muscle (p < 0.05). Exercise did not alter basal PI 3-kinase activity in either white or red muscle. However, in response to exercise, insulin-stimulated PI 3-kinase activity was significantly increased in both muscle fibers (p < 0.05). These results suggest that increased insulin responsiveness induced by exercise may be due, in part, to enhanced insulin-stimulated PI 3-kinase activity.
运动已被证明可增加胰岛素刺激的骨骼肌葡萄糖转运。胰岛素刺激葡萄糖转运需要磷脂酰肌醇3激酶（PI 3激酶）的激活。本研究旨在调查跑步机跑步（60分钟，坡度8%，速度30米/分钟）是否会增强胰岛素刺激的PI 3激酶激活。胰岛素显著增加胰岛素受体底物-1（IRS-1）酪氨酸磷酸化（p<0.05）。跑步机跑步未诱导IRS-1酪氨酸磷酸化，也未改变胰岛素刺激的IRS-1酪氨酸磷酸化。胰岛素使白色肌肉中的PI 3激酶活性增加3.0倍（相对于基础活性），在红色肌肉中增加5.2倍（p<0.05）。运动未改变白色或红色肌肉中的基础PI 3激酶活性。然而，在运动反应中，两种肌纤维中胰岛素刺激的PI 3激酶活性均显著增加（p<0.05）。这些结果表明，运动诱导的胰岛素反应性增加可能部分归因于胰岛素刺激的PI 3激酶活性增强。
