Effects of amino acid administration and exercise on the regulation of the muscle protein and energy metabolism.

通过营养和运动控制代谢可能在促进健康中发挥重要作用，但其作用机制的正确信息是必要的。在本研究中，我们旨在阐明支链氨基酸（BCAA）给药和运动对健康的促进作用及其机制：具体目的是阐明(1)支链氨基酸代谢的调控机制；(2)支链氨基酸对废用性肌肉萎缩的影响；(3)支链氨基酸对葡萄糖代谢的作用。我们发现了一个未知因子的存在，该因子可能通过大鼠肝脏线粒体中支链α-酮酸脱氢酶激酶的失活来调节BCAA的分解代谢。在废用性肌肉萎缩的研究中，我们发现饲喂5% BCAA日粮可以减轻废用性肌肉萎缩引起的促进细胞生长和蛋白质合成因子的减少，尽管它不影响肌肉萎缩本身和泛素-蛋白酶体系统中成分的数量。此外，我们发现血浆BCAA浓度可能在正常葡萄糖耐量中起重要作用。

The metabolic control by nutrition and exercise may play important roles in the health promotion, and its correct information in regard to the responsible mechanisms for the effects are required. In the present studies, we addressed to clarify effects of branched-chain amino acid (BCAA) administration and exercise on the health promotion and the responsible mechanisms for the effects : the detailed aims were to clarify (1) the regulatory mechanism responsible for the BCAA metabolism, (2) the effects of BCAA administration on the disuse-induced muscle atrophy, and (3) the function of BCAA on the glucose metabolism. We found the evidence that suggests the existence of an unknown factor which may regulate the BCAA catabolism through inactivation of the branched-chain α-keto acid dehydrogenase kinase in rat liver mitochondria. In the study for the disuse-induced muscle atrophy, we found that the feeding of 5% BCAA diet attenuated disuse-induced decreases in the factors that promote cell growth and protein synthesis, although it did not affect the muscle atrophy itself and amounts of the components in the ubiquitin-proteasome system. Furthermore, we found that the plasma BCAA concentrations may play an important role in the normal glucose tolerance.