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Cited by 467Muscle metabolism and nutritionNutrition and Health in AgingMuscle Physiology and Disorders

The DOI matches its Crossref record; 53 of the 54 references it cites were found in a registry or an index.

Amino acid ingestion improves muscle protein synthesis in the young and elderly

Paddon-Jones, Douglas, Sheffield-Moore, Melinda, Zhang, Xiao-Jun, Volpi, Elena, Wolf, Steven E., Aarsland, Asle, Ferrando, Arny A., Wolfe, Robert R.·2004·American Journal of Physiology-Endocrinology and Metabolism
DOI 10.1152/ajpendo.00368.2003
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Abstract

We recently demonstrated that muscle protein synthesis was stimulated to a similar extent in young and elderly subjects during a 3-h amino acid infusion. We sought to determine if a more practical bolus oral ingestion would also produce a similar response in young (34 ± 4 yr) and elderly (67 ± 2 yr) individuals. Arteriovenous blood samples and muscle biopsies were obtained during a primed (2.0 μmol/kg) constant infusion (0.05 μmol·kg-1·min-1) of l-[ ring-2 H 5]phenylalanine. Muscle protein kinetics and mixed muscle fractional synthetic rate (FSR) were calculated before and after the bolus ingestion of 15 g of essential amino acids (EAA) in young ( n = 6) and elderly ( n = 7) subjects. After EAA ingestion, the rate of increase in femoral artery phenylalanine concentration was slower in elderly subjects but remained elevated for a longer period. EAA ingestion increased FSR in both age groups by ∼0.04%/h ( P < 0.05). However, muscle intracellular (IC) phenylalanine concentration remained significantly higher in elderly subjects at the completion of the study (young: 115.6 ± 5.4 nmol/ml; elderly: 150.2 ± 19.4 nmol/ml). Correction for the free phenylalanine retained in the muscle IC pool resulted in similar net phenylalanine uptake values in the young and elderly. EAA ingestion increased plasma insulin levels in young (6.1 ± 1.2 to 21.3 ± 3.1 μIU/ml) but not in elderly subjects (3.0 ± 0.6 to 4.3 ± 0.4 μIU/ml). Despite differences in the time course of plasma phenylalanine kinetics and a greater residual IC phenylalanine concentration, amino acid supplementation acutely stimulated muscle protein synthesis in both young and elderly individuals.

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Metadata

Authors
Paddon-Jones, D., Sheffield-Moore, M., Zhang, X.-J., Volpi, E., Wolf, S. E., Aarsland, A., Ferrando, A. A., & Wolfe, R. R.
Affiliations
  • The University of Texas Medical Branch at Galveston (US)
  • Shriners Hospitals for Children - Galveston (US)
  • Shriners Hospitals for Children (US)
ORCID
Venue
American Journal of Physiology-Endocrinology and Metabolism
Publisher
American Physiological Society
Published
2004-03
Volume
286
Issue
3
Pages
E321-E328
ISSN
  • 0193-1849 (ISSN-L)
  • 1522-1555
DOI
10.1152/ajpendo.00368.2003
OpenAlex
W2137789014
Cited by
467
References
54
Citations by year
2026: 7 · 2025: 13 · 2024: 10 · 2023: 16 · 2022: 15 · 2021: 20 · 2020: 24 · 2019: 19 · 2018: 22 · 2017: 18 · 2016: 29 · 2015: 33 · 2014: 29 · 2013: 35 · 2012: 28
FWCI
6.76
Type
journal article
Language
en
Open access
closed
Locations
  • American Journal of Physiology-Endocrinology and Metabolism (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • National Institute on Aging (R01AG018311, P30AG024832)
  • National Institute of General Medical Sciences (5R01 GM 57295, R01GM057295)
  • National Center for Research Resources (M01 RR-00073, M01RR000073)
Topics
  • Health Sciences › Nursing › Nutrition and Dietetics › Muscle metabolism and nutrition
  • Health Sciences › Medicine › Physiology (medical) › Nutrition and Health in Aging
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Muscle Physiology and Disorders
Keywords
muscle protein synthesis, essential amino acids, aging, older adults, phenylalanine kinetics, plasma insulin, amino acid supplementation
MeSH terms
Administration, Oral, Adult, Age Factors, Aged, Aging, Amino Acids, Essential, Female, Humans, Inulin, Male, Muscle Proteins, Phenylalanine

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