| Skeletal muscle protein anabolic response to resistance exercise and essential amino acids is delayed with aging. | |
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MedLine Citation:
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PMID: 18323467 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Skeletal muscle loss during aging leads to an increased risk of falls, fractures, and eventually loss of independence. Resistance exercise is a useful intervention to prevent sarcopenia; however, the muscle protein synthesis (MPS) response to resistance exercise is less in elderly compared with young subjects. On the other hand, essential amino acids (EAA) increase MPS equally in both young and old subjects when sufficient EAA is ingested. We hypothesized that EAA ingestion following a bout of resistance exercise would stimulate anabolic signaling and MPS similarly between young and old men. Each subject ingested 20 g of EAA 1 h following leg resistance exercise. Muscle biopsies were obtained before and 1, 3, and 6 h after exercise to measure the rate of MPS and signaling pathways that regulate translation initiation. MPS increased early in young (1-3 h postexercise) and later in old (3-6 h postexercise). At 1 h postexercise, ERK1/2 MNK1 phosphorylation increased and eIF2alpha phosphorylation decreased only in the young. mTOR signaling (mTOR, S6K1, 4E-BP1, eEF2) was similar between groups at all time points, but MNK1 phosphorylation was lower at 3 h and AMP-activated protein kinase-alpha (AMPKalpha) phosphorylation was higher in old 1-3 h postexercise. We conclude that the acute MPS response after resistance exercise and EAA ingestion is similar between young and old men; however, the response is delayed with aging. Unresponsive ERK1/2 signaling and AMPK activation in old muscle may be playing a role in the delayed activation of MPS. Notwithstanding, the combination of resistance exercise and EAA ingestion should be a useful strategy to combat sarcopenia. |
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Authors:
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Micah J Drummond; Hans C Dreyer; Bart Pennings; Christopher S Fry; Shaheen Dhanani; Edgar L Dillon; Melinda Sheffield-Moore; Elena Volpi; Blake B Rasmussen |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural Date: 2008-03-06 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 104 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2008 May |
Date Detail:
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Created Date: 2008-05-02 Completed Date: 2008-06-17 Revised Date: 2013-02-18 |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 1452-61 Citation Subset: IM |
Affiliation:
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Department of Physical Therapy, Division of Rehabilitation Sciences, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555-1144, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Absorptiometry, Photon Adult Aged Aging / physiology* Algorithms Amino Acids, Essential / pharmacology* Anabolic Agents / pharmacology* Blotting, Western Extracellular Signal-Regulated MAP Kinases / metabolism Glucose / metabolism Glycogen Synthase Kinase 3 / biosynthesis Hormones / blood Humans Hydrocortisone / blood Lactic Acid / metabolism Leucine / blood, pharmacology Male Middle Aged Muscle Proteins / biosynthesis* Muscle, Skeletal / drug effects, growth & development*, metabolism* Phenylalanine / blood Phosphorylation Physical Fitness / physiology* Protein Kinases / biosynthesis RNA / biosynthesis, isolation & purification Signal Transduction / drug effects, physiology TOR Serine-Threonine Kinases |
| Grant Support | |
ID/Acronym/Agency:
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P30 AG 024832/AG/NIA NIH HHS; P30 AG024832-04/AG/NIA NIH HHS; R01 AG 018311/AG/NIA NIH HHS; R01 AG018311-10/AG/NIA NIH HHS; R01 AG018311-13/AG/NIA NIH HHS; R01 AR 049877/AR/NIAMS NIH HHS; R01 AR049877-04/AR/NIAMS NIH HHS; T32 HD007539/HD/NICHD NIH HHS; T32 HD007539-08/HD/NICHD NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Amino Acids, Essential; 0/Anabolic Agents; 0/Hormones; 0/Muscle Proteins; 50-21-5/Lactic Acid; 50-23-7/Hydrocortisone; 50-99-7/Glucose; 61-90-5/Leucine; 63-91-2/Phenylalanine; 63231-63-0/RNA; EC 2.7.-/Protein Kinases; EC 2.7.1.1/MTOR protein, human; EC 2.7.1.1/TOR Serine-Threonine Kinases; EC 2.7.11.1/glycogen synthase kinase 3 beta; EC 2.7.11.24/Extracellular Signal-Regulated MAP Kinases; EC 2.7.11.26/Glycogen Synthase Kinase 3 |
| Comments/Corrections | |
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