Functional regulation of L-leucine supplementation and mechanical stress on skeletal muscle cells

Abstract

Appropriate exercise and nutritional intake are required to maintain the health of locomotor system, including skeletal muscle, in aged people. Sarcopenia, characterized by age-related loss of skeletal muscle mass and function, can be prevented by both exercise and nutritional approaches; however, the mechanism remains unclear. Branched-chain amino acids (BCAA) intake after resistance training promotes muscle protein synthesis, and free BCAA in blood and cells have been reported to exhibit various physiological functions. Most ingested amino acids are metabolized in the liver, while BCAA are metabolized in skeletal muscle. Recently, metabolites derived from L-leucine, one of the BCAA, have been shown to activate mTORC1 (mechanistic target of rapamycin complex 1) pathway and accelerate myogenesis. In this review, we summarize the effects of BCAA and mechanical stimulation on skeletal muscle cells.