Exercise induces a transient increase in transcription of the GLUT-4 gene in skeletal muscle.
Exercise induces a transient increase in transcription of the GLUT-4 gene in skeletal muscle.
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DOI：
10.1152/ajpcell.1993.265.6.c1597
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发表时间：
1993-12
期刊：
影响因子：
--
通讯作者：
P. Neufer;G. Dohm
中科院分区：
文献类型：
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作者：
P. Neufer;G. Dohm
耐力运动训练使骨骼肌线粒体密度增加，Glut-4葡萄糖转运蛋白含量增加。呼吸酶和GLUT-4的mRNA相应增加表明翻译前控制机制参与了这一适应过程。为了直接检测GLUT-4基因的转录是否被运动训练激活，在运动1wk(8%等级，32m/min，40min，2次/d)后，从大鼠的红色后肢骨骼肌中分离出细胞核。在最后一次训练后30分钟、3小时或24小时处死大鼠。GLUT-4转录水平在运动后30min无明显变化，运动后3h增加1.8倍，但与对照组相比差异无统计学意义。在单次运动后，未训练大鼠的GLUT-4基因转录也有类似的一过性增加，但不那么明显(1.4倍)，这表明运动训练增强了运动后GLUT-4基因转录的诱导。训练1wk后，GLUT-4蛋白含量增加1.7倍，而GLUT-4 mRNA没有任何相应的变化，这表明GLUT-4表达的最初增加涉及翻译和/或翻译后控制机制。这些发现表明，肌肉GLUT-4在运动训练中的表达同时受到转录和转录后调控。我们认为，随着训练时间的延长，GLUT-4mRNA的明显增加可能是由于转向翻译前控制，是运动后GLUT-4基因转录的反复瞬时增加的累积效应。
Endurance exercise training elicits an increase in mitochondrial density as well as GLUT-4 glucose transporter protein content in skeletal muscle. Corresponding increases in mRNA for respiratory enzymes and GLUT-4 indicate that pretranslational control mechanisms are involved in this adaptive process. To directly test whether transcription of the GLUT-4 gene is activated in response to exercise training, nuclei were isolated from red hindlimb skeletal muscle of rats after 1 wk of exercise training (8% grade, 32 m/min, 40 min, twice/day). Rats were killed either 30 min, 3 h, or 24 h after the last training session. GLUT-4 transcription, determined by nuclear run-on analysis, was unaltered after 30 min, increased by 1.8-fold after 3 h, but was no longer different from controls 24 h after exercise. A similar transient increase in GLUT-4 transcription was evident, but less pronounced (1.4-fold), in untrained rats after a single bout of exercise, suggesting that the postexercise induction in GLUT-4 gene transcription is enhanced by exercise training. GLUT-4 protein content was increased 1.7-fold after 1 wk of training in the absence of any corresponding change in GLUT-4 mRNA, providing evidence that the initial increase in GLUT-4 expression involves translational and/or posttranslational control mechanisms. These findings demonstrate that muscle GLUT-4 expression in response to exercise training is subject to both transcriptional and posttranscriptional regulation. We propose that the increase in GLUT-4 mRNA evident with extended periods of training may result from a shift to pretranslational control and is the cumulative effect of repeated postexercise transient increases in GLUT-4 gene transcription.