Abstract
The anabolic effect of essential amino acids (EAA) in connection with resistance exercise is well documented. Among the EAA, leucine has been suggested to play a key role, however, this has not previously been studied in female subjects. The aim of this study was to compare the effect of EAA with and without leucine (EAA‐leu) on the anabolic response through the mammalian target of rapamycin (mTOR) signaling pathway. In addition, gene expression of two ubiquitin ligases (MAFbx and MuRF‐1) was measured as they are involved in muscle protein breakdown. Eight female subjects performed leg press exercise twice, separated by one month, during which they were randomly supplied one of the two supplements in flavored water. Muscle biopsies were taken from the vastus lateralis before exercise and 1 and 3h following exercise. Ingestion of EAA led to a 3‐fold larger increase (p<0.05) in p70S6k phosphorylation 1h after exercise, whereas phosphorylation of mTOR increased similarly in both conditions. The mRNA content of the two ubiquitin ligases was reduced 3h following exercise (MAFbx 35%, ns and MuRF‐1 40%, p<0.05) when a mixture of EAA was ingested, but no significant changes were seen when EAA‐leu was ingested. The results support the idea that leucine has a particularly important role in stimulating p70S6k, a key enzyme regulating protein translation, but may also reduce expression of genes involved in protein degradation.The study was supported by funds from the Swedish School of Sport and Health Sciences, Stockholm, Sweden.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call