Leucine-enriched Amino acid ingestion after resistance exercise prolongs myofibrillar protein synthesis and amino acid transporter expression in older men

Jared Dickinson, David M. Gundermann, Dillon K. Walker, Paul T. Reidy, Michael S. Borack, Micah J. Drummond, Mohit Arora, Elena Volpi, Blake B. Rasmussen

    Research output: Contribution to journalArticlepeer-review

    59 Scopus citations

    Abstract

    Background: Postexercise protein or amino acid ingestion restores muscle protein synthesis in older adults and represents an important therapeutic strategy for aging muscle. However, the precise nutritional factors involved are unknown. Objective: The purpose of this study was to determine the role of increased postexercise Leu ingestion on skeletal muscle myofibrillar protein synthesis (MyoPS), mammalian/mechanistic target of rapamycin complex 1 signaling, and amino acid transporter (AAT) mRNA expression in older men over a 24-h post-resistance exercise (RE) time course. Methods: During a stable isotope infusion trial (L-[ring-13C6]Phe; L-[1-13C]Leu), older men performed RE and, at 1 h after exercise, ingested 10 g of essential amino acids (EAAs) containing either a Leu content similar to quality protein (control, 1.85 g of Leu, n=7) or enriched Leu (LEU; 3.5 g of Leu, n = 8). Muscle biopsies (vastus lateralis) were obtained at rest and 2, 5, and 24 h after exercise. Results: p70 S6 kinase 1 phosphorylation was increased in each group at 2 h (P > 0.05), whereas 4E binding protein 1 phosphorylation increased only in the LEU group (P > 0.05).MyoPS was similarly increased (~90%) above basal in each group at 5 h (P >0.05) and remained elevated (~90%) at 24 h only in the LEU group (P > 0.05). The mRNA expression of select AATs was increased at 2 and 5 h in each group (P > 0.05), but AAT expression was increased at 24 h only in the LEU group (P < 0.05). Conclusions: Leu-enriched EAA ingestion after RE may prolong the anabolic response and sensitivity of skeletal muscle to amino acids in older adults. These data emphasize the potential importance of adequate postexercise Leu ingestion to enhance the response of aging muscle to preventive or therapeutic exercise-based rehabilitation programs.

    Original languageEnglish (US)
    Pages (from-to)1694-1702
    Number of pages9
    JournalJournal of Nutrition
    Volume144
    Issue number11
    DOIs
    StatePublished - 2014

    ASJC Scopus subject areas

    • Medicine (miscellaneous)
    • Nutrition and Dietetics

    Fingerprint Dive into the research topics of 'Leucine-enriched Amino acid ingestion after resistance exercise prolongs myofibrillar protein synthesis and amino acid transporter expression in older men'. Together they form a unique fingerprint.

    Cite this