EFFECTS OF EXERCISE TRAINING ON MUSCLE GLUT-4 PROTEIN-CONTENT AND TRANSLOCATION IN OBESE ZUCKER RATS
EFFECTS OF EXERCISE TRAINING ON MUSCLE GLUT-4 PROTEIN-CONTENT AND TRANSLOCATION IN OBESE ZUCKER RATS
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DOI：
10.1152/ajpendo.1993.265.3.e419
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发表时间：
1993-09-01
影响因子：
--
通讯作者：
IVY, JL
中科院分区：
文献类型：
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作者：
BROZINICK, JT;ETGEN, GJ;IVY, JL
通过在基础条件下（无胰岛素）、存在最大刺激浓度的胰岛素（10 mU/ml）和通过电刺激坐骨神经引起的肌肉收缩后的后肢灌注来评估训练的（TR）和未训练的（UT）肥胖Zucker大鼠的肌肉葡萄糖摄取速率。灌注液含有28 mM葡萄糖和7.5 μ Ci/mmol 2-脱氧-D-[H-3]葡萄糖。通过蛋白质印迹分析测定肌肉GLUT-4浓度，并表示为心脏标准品的百分比。与UT大鼠相比，TR大鼠的跖肌、红腓肠肌（RG）和白色腓肠肌（WG）的胰岛素刺激葡萄糖摄取率显著更高，但比目鱼肌或趾长伸肌（EDL）的胰岛素刺激葡萄糖摄取率不显著更高。肌肉收缩后，TR大鼠的比目鱼肌、跖肌和RG的葡萄糖摄取率显著较高。TR大鼠在比目鱼肌、跖肌、RG和WG中的GLUT-4蛋白浓度和柠檬酸合酶活性显著高于UT大鼠。TR组大鼠基底膜GLUT-4蛋白含量为UT组的144%（P < 0.01）。胰岛素刺激和收缩仅导致UT大鼠质膜GLUT-4蛋白浓度显着增加。而胰岛素刺激和收缩刺激TR大鼠的质膜GLUT-4蛋白浓度分别比UT大鼠高53%和30%（P < 0.05）。运动训练没有改变基础，胰岛素，或收缩刺激的GLUT-4功能活性。这些结果表明，有氧运动训练后胰岛素和收缩刺激的肌肉葡萄糖摄取增加部分是由于质膜GLUT-4蛋白浓度增加，而不是GLUT-4蛋白易位增加或GLUT-4功能活性增强。
The rates of muscle glucose uptake of trained (TR) and untrained (UT) obese Zucker rats were assessed by hindlimb perfusion under basal conditions (no insulin) in the presence of a maximally stimulating concentration of insulin (10 mU/ml) and after muscle contraction elicited by electrical stimulation of the sciatic nerve. Perfusate contained 28 mM glucose and 7.5 muCi/mmol of 2-deoxy-D-[H-3]glucose. Muscle GLUT-4 concentration was determined by Western blot analysis and expressed as a percentage of a heart standard. The rates of insulin-stimulated glucose uptake were significantly higher in the plantaris, red gastrocnemius (RG), and white gastrocnemius (WG), but not the soleus or extensor digatorum longus (EDL) of TR compared with UT rats. After muscle contraction the rates of glucose uptake in the TR rats were significantly higher in the soleus, plantaris, and RG. TR rats had significantly higher GLUT-4 protein concentration and citrate synthase activity than the UT rats in the soleus, plantaris, RG, and WG. Basal plasma membrane GLUT-4 protein concentration of TR rats was 144% above UT rats (P < 0.01). Stimulation by insulin and contraction resulted in a significant increase in plasma membrane GLUT-4 protein concentration in UT rats only. However, plasma membrane GLUT-4 protein concentration in insulin- and contraction-stimulated TR rats remained 53% and 30% greater than that of UT rats, respectively (P < 0.05). Exercise training did not alter basal, insulin-, or contraction-stimulated GLUT-4 functional activity. These results indicate that the increases in insulin- and contraction-stimulated muscle glucose uptake after aerobic exercise training were due in part to an increased plasma membrane GLUT-4 protein concentration and not to an increased GLUT-4 protein translocation or enhanced GLUT-4 functional activity.