Document Detail


A new method to study in vivo protein synthesis in slow- and fast-twitch muscle fibers and initial measurements in humans.
MedLine Citation:
PMID:  20203068     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The aim of this study was to develop an approach to directly assess protein fractional synthesis rate (FSR) in isolated human muscle fibers in a fiber type-specific fashion. Individual muscle fibers were isolated from biopsies of the vastus lateralis (VL) and soleus (SOL) obtained from eight young men during a primed, continuous infusion of [5,5,5-(2)H3]leucine performed under basal conditions. To determine mixed protein FSR, a portion of each fiber was used to identify fiber type, fibers of the same type were pooled, and the [5,5,5-(2)H3]leucine enrichment was determined via GC-MS. Processing isolated slow-twitch [myosin heavy chain (MHC) I] and fast-twitch (MHC IIa) fibers for mixed protein bound [5,5,5-(2)H3]leucine enrichment yielded mass ion chromatographic peaks that were similar in shape, abundance, and measurement reliability as tissue homogenates. In the VL, MHC I fibers exhibited a 33% faster (P<0.05) mixed protein FSR compared with MHC IIa fibers (0.068+/-0.006 vs. 0.051+/-0.003%/h). MHC I fibers from the SOL (0.060+/-0.005%/h) and MHC I fibers from the VL displayed similar (P>0.05) mixed protein FSR. Feasibility of processing isolated human muscle fibers for analysis of myofibrillar protein [5,5,5-(2)H3]leucine enrichment was also confirmed in non-fiber-typed pooled fibers from the VL. These methods can be applied to the study of fiber type-specific responses in human skeletal muscle. The need for this level of investigation is underscored by the different contributions of each fiber type to whole muscle function and the numerous distinct adaptive functional and metabolic changes in MHC I and MHC II fibers originating from the same muscle.
Authors:
J M Dickinson; J D Lee; B E Sullivan; M P Harber; S W Trappe; T A Trappe
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2010-03-04
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  108     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2010 May 
Date Detail:
Created Date:  2010-05-05     Completed Date:  2010-08-12     Revised Date:  2011-07-28    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1410-6     Citation Subset:  IM    
Affiliation:
Human Performance Laboratory, Ball State University, Muncie, IN 47306, USA.
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MeSH Terms
Descriptor/Qualifier:
Biopsy
Feasibility Studies
Gas Chromatography-Mass Spectrometry*
Humans
Infusions, Intravenous
Keto Acids / blood
Kinetics
Leucine / administration & dosage,  blood
Male
Muscle Fibers, Fast-Twitch / metabolism*
Muscle Fibers, Slow-Twitch / metabolism*
Myosin Heavy Chains / biosynthesis*
Myosin Type I / biosynthesis*
Quadriceps Muscle / cytology,  metabolism*
Skeletal Muscle Myosins / biosynthesis*
Tritium
Young Adult
Grant Support
ID/Acronym/Agency:
R01-AG-020532/AG/NIA NIH HHS
Chemical
Reg. No./Substance:
0/Keto Acids; 0/Myosin Heavy Chains; 10028-17-8/Tritium; 61-90-5/Leucine; 816-66-0/alpha-ketoisocaproic acid; EC 3.6.1.-/Myosin Type I; EC 3.6.1.-/Skeletal Muscle Myosins
Comments/Corrections

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


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