Exogenous amino acids stimulate net muscle protein synthesis in the elderly

Elena Volpi, Arny A. Ferrando, Catherine W. Yeckel, Kevin D. Tipton, Robert R. Wolfe

Research output: Contribution to journalArticle

312 Citations (Scopus)

Abstract

We have investigated the response of amino acid transport and protein synthesis in healthy elderly individuals (age 71±2 yr) to the stimulatory effect of increased amino acid availability. Muscle protein synthesis and breakdown, and amino acid transport were measured in the postabsorptive state and during the intravenous infusion of an amino acid mixture. Muscle-free amino acid kinetics were calculated by means of a three compartment model using data obtained by femoral arterio-venous catheterization and muscle biopsics from the vastus lateralis during the infusion of stable isotope tracers of amino acids. In addition, muscle protein fractional synthetic rate (FSR) was measured. Peripheral amino acid infusion significantly increased amino acid delivery to the leg, amino acid transport, and muscle protein synthesis when measured either with the three compartment model (P < 0.05) or with the traditional precursor-product approach (FSR increased from 0.0474±0.0054 to 0.0940±0.0143%/h, P < 0.05). Because protein breakdown did not change during amino acid infusion, a positive net balance of amino acids across the muscle was achieved. We conclude that, although muscle mass is decreased in the elderly, muscle protein anabolism can nonetheless be stimulated by increased amino acid availability. We thus hypothesize that muscle mass could be better maintained with an increased intake of protein or amino acids.

Original languageEnglish (US)
Pages (from-to)2000-2007
Number of pages8
JournalJournal of Clinical Investigation
Volume101
Issue number9
StatePublished - May 1 1998

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Muscle Proteins
Amino Acids
Muscles
Carrier Proteins
Quadriceps Muscle
Thigh
Intravenous Infusions
Catheterization
Isotopes
Leg
Proteins

Keywords

  • Aging
  • Metabolism
  • Stable isotopes
  • Tracers
  • Transport

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Volpi, E., Ferrando, A. A., Yeckel, C. W., Tipton, K. D., & Wolfe, R. R. (1998). Exogenous amino acids stimulate net muscle protein synthesis in the elderly. Journal of Clinical Investigation, 101(9), 2000-2007.

Exogenous amino acids stimulate net muscle protein synthesis in the elderly. / Volpi, Elena; Ferrando, Arny A.; Yeckel, Catherine W.; Tipton, Kevin D.; Wolfe, Robert R.

In: Journal of Clinical Investigation, Vol. 101, No. 9, 01.05.1998, p. 2000-2007.

Research output: Contribution to journalArticle

Volpi, E, Ferrando, AA, Yeckel, CW, Tipton, KD & Wolfe, RR 1998, 'Exogenous amino acids stimulate net muscle protein synthesis in the elderly', Journal of Clinical Investigation, vol. 101, no. 9, pp. 2000-2007.
Volpi E, Ferrando AA, Yeckel CW, Tipton KD, Wolfe RR. Exogenous amino acids stimulate net muscle protein synthesis in the elderly. Journal of Clinical Investigation. 1998 May 1;101(9):2000-2007.
Volpi, Elena ; Ferrando, Arny A. ; Yeckel, Catherine W. ; Tipton, Kevin D. ; Wolfe, Robert R. / Exogenous amino acids stimulate net muscle protein synthesis in the elderly. In: Journal of Clinical Investigation. 1998 ; Vol. 101, No. 9. pp. 2000-2007.
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