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Dose-dependent increases in p70S6K phosphorylation and intramuscular branched-chain amino acids in older men following resistance exercise and protein intake

D'Souza, Randall F, Marworth, James F, Figueiredo, Vandre C, Della Gatta, Paul A, Petersen, Aaron C, Mitchell, Cameron J and Cameron-Smith, David 2014, Dose-dependent increases in p70S6K phosphorylation and intramuscular branched-chain amino acids in older men following resistance exercise and protein intake, Physiological Reports, vol. 2, no. 8, pp. 1-12, doi: 10.14814/phy2.12112.

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Title Dose-dependent increases in p70S6K phosphorylation and intramuscular branched-chain amino acids in older men following resistance exercise and protein intake
Author(s) D'Souza, Randall F
Marworth, James F
Figueiredo, Vandre C
Della Gatta, Paul AORCID iD for Della Gatta, Paul A orcid.org/0000-0003-2231-8370
Petersen, Aaron C
Mitchell, Cameron J
Cameron-Smith, David
Journal name Physiological Reports
Volume number 2
Issue number 8
Start page 1
End page 12
Total pages 12
Publisher Wiley
Place of publication England, London
Publication date 2014-08-07
ISSN 2051-817X
Keyword(s) Leucine
mammalian target of rapamycin
mass spectrometry
muscle mass
protein synthesis
sarcopenia
Summary Resistance exercise and whey protein supplementation are effective strategies to activate muscle cell anabolic signaling and ultimately promote increases in muscle mass and strength. In the current study, 46 healthy older men aged 60–75 (69.0 ± 0.55 years, 85.9 ± 1.8 kg, 176.8 ± 1.0 cm) performed a single bout of unaccustomed lower body resistance exercise immediately followed by ingestion of a noncaloric placebo beverage or supplement containing 10, 20, 30, or 40 g of whey protein concentrate (WPC). Intramuscular amino acid levels in muscle biopsy samples were measured by Gas Chromatography–Mass Spectrometry (GC-MS) at baseline (before exercise and WPC supplementation) plus at 2 h and 4 h post exercise. Additionally, the extent of p70S6K phosphorylation at Thr389 in muscle biopsy homogenates was assessed by western blot. Resistance exercise alone reduced intramuscular branch chain amino acid (BCAA; leucine, isoleucine, and valine) content. Supplementation with increasing doses of whey protein prevented this fall in muscle BCAAs during postexercise recovery and larger doses (30 g and 40 g) significantly augmented postexercise muscle BCAA content above that observed following placebo ingestion. Additionally, the fold change in the phosphorylation of p70S6K (Thr389) at 2 h post exercise was correlated with the dose of whey protein consumed (r = 0.51, P < 001) and was found to be significantly correlated with intramuscular leucine content (r = 0.32, P = 0.026). Intramuscular BCAAs, and leucine in particular, appear to be important regulators of anabolic signaling in aged human muscle during postexercise recovery via reversal of exercise-induced declines in intramuscular BCAAs.
Language eng
DOI 10.14814/phy2.12112
Field of Research 110699 Human Movement and Sports Science not elsewhere classified
Socio Economic Objective 920504 Men's Health
HERDC Research category C1 Refereed article in a scholarly journal
ERA Research output type C Journal article
Copyright notice ©2014, The Authors
Free to Read? Yes
Use Rights Creative Commons Attribution licence
Persistent URL http://hdl.handle.net/10536/DRO/DU:30067263

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Every reasonable effort has been made to ensure that permission has been obtained for items included in DRO. If you believe that your rights have been infringed by this repository, please contact drosupport@deakin.edu.au.