Regulation of Skeletal Muscle Function by Amino Acids
Regulation of Skeletal Muscle Function by Amino Acids
复制标题
DOI：
10.3390/nu12010261
复制
发表时间：
2020-01-01
期刊：
影响因子：
5.9
通讯作者：
Miura, Shinji
中科院分区：
文献类型：
--
作者：
Kamei, Yasutomi;Hatazawa, Yukino;Miura, Shinji
氨基酸是蛋白质的组成部分，也以自由形式存在于体内；它们的功能可分为(1)营养作用、(2)感觉作用和(3)生物调节作用。骨骼肌是人体最大的器官，约占总体重的40%，在运动、能量消耗和葡萄糖/氨基酸利用过程中发挥着重要作用，这些过程受到各种氨基酸及其代谢物的调节。在这篇综述中，我们讨论了氨基酸在骨骼肌中的代谢和功能。在运动过程中，转录辅助激活因子PGC1α在骨骼肌中的表达增加。PGC1α激活支链氨基酸(BCAA)代谢，在三羧酸(TCA)循环中用作能量。支链氨基酸亮氨酸及其代谢产物β-羟基-β-甲基丁酸酯(HMB)均能激活哺乳动物靶标雷帕霉素复合体1(MTORC1)，促进蛋白质合成，但激活机制不同。Valine(另一种支链氨基酸)的代谢物，β-氨基异丁酸(BAIBA)，通过运动增加，由骨骼肌分泌，并作用于其他组织，如白色脂肪组织，以增加能量消耗。此外，据报道，一些与氨基酸相关的分子可以激活骨骼肌功能。口服5-氨基乙酰丙酸(ALA)可以预防轻度高血糖，有助于预防2型糖尿病。老年小鼠骨骼肌中的β-丙氨酸水平降低。补充β-丙氨酸可提高中年人耐力运动后的体能，改善执行功能。关于氨基酸及其代谢物对骨骼肌功能影响的进一步研究将为老年人、运动员和患有代谢性疾病的个人生产食品补充剂提供必要的数据。
Amino acids are components of proteins that also exist free-form in the body; their functions can be divided into (1) nutritional, (2) sensory, and (3) biological regulatory roles. The skeletal muscle, which is the largest organ in the human body, representing similar to 40% of the total body weight, plays important roles in exercise, energy expenditure, and glucose/amino acid usage-processes that are modulated by various amino acids and their metabolites. In this review, we address the metabolism and function of amino acids in the skeletal muscle. The expression of PGC1 alpha, a transcriptional coactivator, is increased in the skeletal muscle during exercise. PGC1 alpha activates branched-chain amino acid (BCAA) metabolism and is used for energy in the tricarboxylic acid (TCA) cycle. Leucine, a BCAA, and its metabolite, beta-hydroxy-beta-methylbutyrate (HMB), both activate mammalian target of rapamycin complex 1 (mTORC1) and increase protein synthesis, but the mechanisms of activation appear to be different. The metabolite of valine (another BCAA), beta-aminoisobutyric acid (BAIBA), is increased by exercise, is secreted by the skeletal muscle, and acts on other tissues, such as white adipose tissue, to increase energy expenditure. In addition, several amino acid-related molecules reportedly activate skeletal muscle function. Oral 5-aminolevulinic acid (ALA) supplementation can protect against mild hyperglycemia and help prevent type 2 diabetes. beta-alanine levels are decreased in the skeletal muscles of aged mice. beta-alanine supplementation increased the physical performance and improved the executive function induced by endurance exercise in middle-aged individuals. Further studies focusing on the effects of amino acids and their metabolites on skeletal muscle function will provide data essential for the production of food supplements for older adults, athletes, and individuals with metabolic diseases.