Document Detail

Mixed muscle and hepatic derived plasma protein metabolism is differentially regulated in older and younger men following resistance exercise.
MedLine Citation:
PMID:  15644460     Owner:  NLM     Status:  MEDLINE    
We sought to determine whether exercise-induced muscle protein turnover alters the subsequent production of hepatically derived acute-phase plasma proteins, and whether age affects how these proteins are regulated. We measured arteriovenous (a-v) balance and the synthesis of mixed muscle protein, albumin (A) and fibrinogen (F) before exercise (REST) and from the beginning of exercise to 10, 60, and 180 min following a single bout of moderate-intensity leg extension exercise (POST-EX) in postabsorptive untrained older (n = 6) and younger (n = 6) men using L-[ring-2H5]phenylalanine (Phe). Subjects performed 6 sets of 8 repetitions of leg extension at 80% of their 1-RM (one-repetition maximum). All data are presented as the difference from REST (Delta from REST at 10, 60, and 180 min POST-EX). Mixed muscle fractional synthesis rate (FSR-M) increased significantly from the beginning of exercise until 10 min POST-EX in the older men (DeltaFSR-M: 0.044%/h), whereas FSR-M in the younger men was not elevated until 180 min POST-EX (DeltaFSR-M: 0.030%/h). FSR-A and FSR-F increased at all POST-EX periods in the older men (DeltaFSR-A = 10 min: 1.90%/day; 60 min: 2.72%/day; 180 min: 2.78%/day; DeltaFSR-F = 10 min: 1.00%/day; 60 min: 3.01%/day; 180 min: 3.73%/day). No change occurred in FSR-A in the younger men, but FSR-F was elevated from the beginning of exercise until 10 and 180 min POST-EX (10 min: 3.07%/day and 180 min: 3.96%/day). Net balance of Phe was positive in the older men in the immediate POST-EX period. Our data indicate that mixed muscle and hepatic derived protein synthesis is differentially regulated in younger and older men in response to a single bout of moderate-intensity leg extension exercise. Moreover, our data suggest that with age may come a greater need to salvage or make available amino acids from exercise-induced muscle protein breakdown to mount an acute-phase response.
M Sheffield-Moore; D Paddon-Jones; A P Sanford; J I Rosenblatt; A G Matlock; M G Cree; R R Wolfe
Publication Detail:
Type:  Clinical Trial; Comparative Study; Controlled Clinical Trial; Journal Article; Research Support, U.S. Gov't, P.H.S.     Date:  2005-01-11
Journal Detail:
Title:  American journal of physiology. Endocrinology and metabolism     Volume:  288     ISSN:  0193-1849     ISO Abbreviation:  Am. J. Physiol. Endocrinol. Metab.     Publication Date:  2005 May 
Date Detail:
Created Date:  2005-04-11     Completed Date:  2005-05-18     Revised Date:  2014-07-17    
Medline Journal Info:
Nlm Unique ID:  100901226     Medline TA:  Am J Physiol Endocrinol Metab     Country:  United States    
Other Details:
Languages:  eng     Pagination:  E922-9     Citation Subset:  IM; S    
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MeSH Terms
Aging / physiology*
Albumins / analysis*
Blood Proteins / analysis
Exercise Test
Fibrinogen / analysis*
Gene Expression Regulation / physiology
Liver / metabolism*
Metabolic Clearance Rate
Muscle Proteins / blood*
Muscle, Skeletal / physiology*
Physical Exertion / physiology*
Grant Support
M01-RR-00073/RR/NCRR NIH HHS; P30 AG024832/AG/NIA NIH HHS; P60-AG-17231-01/AG/NIA NIH HHS; R01-AG21539/AG/NIA NIH HHS
Reg. No./Substance:
0/Albumins; 0/Blood Proteins; 0/Muscle Proteins; 9001-32-5/Fibrinogen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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