Effects of glucocorticoids on muscle protein turnover in perfused rat hemicorpus.
Effects of glucocorticoids on muscle protein turnover in perfused rat hemicorpus.
复制标题
糖皮质激素对灌注大鼠半体肌肉蛋白周转的影响。
DOI：
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发表时间：
1980
影响因子：
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通讯作者：
L. Jefferson
中科院分区：
文献类型：
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作者：
S. Rannels;L. Jefferson
正常和肾上腺切除的大鼠用可的松治疗，每天失去2%的初始体重，而对照组体重以2%/天的速度增加。五天的治疗导致一些混合纤维型肌肉的重量减少25%，但不影响心脏或比目鱼肌（由慢收缩红色纤维组成的肌肉）的重量。肌肉重量的减少伴随着蛋白质和RNA的损失。接受5天治疗的大鼠的灌注半体制剂释放了比对照组更大量的几种氨基酸。类固醇治疗3或5天后，灌注腓肠肌中的蛋白质合成减少50-60%。这种减少是由于RNA的损失和抑制翻译造成的损害在肽链起始。与此相反，RNA含量和启动没有改变心脏和比目鱼肌。蛋白质降解灌注hemicorpus和组织蛋白酶D活性在腓肠肌不受可的松治疗，这表明肌肉重量和蛋白质含量的损失，以及增加氨基酸释放导致蛋白质合成减少。
Normal and adrenalectomized rats treated with cortisone lost 2% of their initial body weight per day, whereas controls gained weight at a rate of 2%/day. Five days of treatment resulted in a 25% reduction in the weights of a number of mixed fiber type muscles, but did not affect the weights of heart or soleus, a muscle consisting of slow-twitch red fibers. Reductions in muscle weights were accompanied by a loss of protein and RNA. Perfused hemicorpus preparations from rats receiving 5 days of treatment released several amino acids in greater amounts than the controls. Protein synthesis in perfused gastrocnemius was reduced 50-60% after 3 or 5 days of steroid treatment. This reduction was due to a loss of RNA and to an inhibition of translation resulting from an impairment in peptide-chain initiation. In contrast, RNA content and initiation were not altered in heart and soleus. Protein degradation in perfused hemicorpus and cathepsin D activity in gastrocnemius were unaffected by cortisone treatment, suggesting that loss of muscle weight and protein content as well as increased amino acid release resulted from the reduction in protein synthesis.