Different response of amino acids on muscle protein synthesis and degradation under nutritional stresses

营养应激下氨基酸对肌肉蛋白质合成和降解的不同反应

基本信息

批准号：
18580110
负责人：
NAGASAWA Takashi
金额：
$ 2.47万
依托单位：
Iwate University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18580110/
关键词：
muscle amino acids leucine protein synthesis protein degradation

项目摘要

1. The function of leucine under low nutritional conditions Skeletal muscle weight decreased in feeding of one week protein free diet, however the weight loss was suppressed in 1.5% leucine supplementation. Muscle protein degradation evaluated by A-V difference of 3-methylhistidine concentration was also suppressed by leucine supplemented diet. The rate of muscle protein synthesis was not changed. Although ubiquitin-proteasome expression and calpain activity were not reduced in feeding of leucine supplemented diet, LC-3II expression was decreased. These results suggested that leucine enhances muscle protein degradation rather synthesis and the degradation might be regulated by autophagy in low nutritional conditions.2. Effects of repeated leucine consumption on muscle protein synthesis and degrdation Six hours interval leucine administration to rats decreased myofibrillar protein degradation evaluated by 3-methylhistidine release from the isolated muscle. However, synthesis evaluated by phosphrylation of S6K1 did not, suggesting that repeated leucine supplementation is beneficial for muscle atrophy.3. Effects of leucine on muscle atrophy in disuse model Immobilization of hind limb increased muscle protein degradation and then resulted muscle atrophy. In this model, leucine supplemented diet attenuated muscle atrophy due to muscle protein degradation especially ubiquitin-proteasome.

1。亮氨酸在低营养条件下的功能骨骼肌体重降低了一周的蛋白质饮食，但是补充1.5％的亮氨酸抑制了体重减轻。亮氨酸补充饮食还抑制了通过3-甲基组织浓度的A-V差异评估的肌肉蛋白降解。肌肉蛋白合成的速率没有改变。尽管泛素 - 蛋白酶体的表达和钙蛋白酶活性并未降低亮氨酸补充饮食，但LC-3II表达降低。这些结果表明，亮氨酸会增强肌肉蛋白降解而不是合成，并且在低营养状况下自噬可能会调节降解。2。反复亮氨酸消耗对肌肉蛋白合成和降解的影响六个小时间隔亮氨酸对大鼠的降低降低了肌原纤维蛋白降解，这些蛋白质通过从分离的肌肉中释放出3-甲基激素释放而评估。然而，通过S6K1磷酸化评估的合成没有，这表明补充重复的亮氨酸对肌肉萎缩有益3。亮氨酸对后肢固定模型的肌肉萎缩的影响增加了肌肉蛋白降解，然后导致肌肉萎缩。在该模型中，亮氨酸补充饮食会导致肌肉蛋白质降解，尤其是泛素 - 蛋白酶体，导致肌肉萎缩。