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

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
Open this paper in CoChat — free account

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.

Integrity signals

Registry

Crossref · 10.1152/ajpendo.00368.2003

Cites

53 of 53 references verified0 citation errors · 0 not checkable

Statistics

Recomputing p-values needs the paper’s full text.

Claims the paper makes

We couldn’t retrieve this paper’s full text, so its claims and self-check weren’t run. The registry and citation checks still apply.

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Cites

Flagged first, then by citations

1 of the 54 references couldn’t be matched to a known paper.

Cited by

Sorted by citations

Related

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
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Muscle metabolism and nutrition
  • Health Sciences › Medicine › Physiology › 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

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review