| Exogenous amino acids stimulate net muscle protein synthesis in the elderly. | |
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MedLine Citation:
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PMID: 9576765 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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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 biopsies 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. |
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Authors:
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E Volpi; A A Ferrando; C W Yeckel; K D Tipton; R R Wolfe |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: The Journal of clinical investigation Volume: 101 ISSN: 0021-9738 ISO Abbreviation: J. Clin. Invest. Publication Date: 1998 May |
Date Detail:
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Created Date: 1998-06-08 Completed Date: 1998-06-08 Revised Date: 2009-11-18 |
Medline Journal Info:
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Nlm Unique ID: 7802877 Medline TA: J Clin Invest Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 2000-7 Citation Subset: AIM; IM; S |
Affiliation:
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Department of Surgery, The University of Texas Medical Branch, Galveston, Texas 77550, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Aged Amino Acids / metabolism, pharmacokinetics, pharmacology* Biological Transport Biopsy Catheters, Indwelling Humans Infusions, Intravenous Leg Male Models, Biological Muscle Proteins / biosynthesis* Muscle, Skeletal / drug effects*, metabolism |
| Grant Support | |
ID/Acronym/Agency:
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M0IRR00073/RR/NCRR NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Amino Acids; 0/Muscle Proteins |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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