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Reduced Plasma Free Fatty Acid Availability During Exercise: Effect on Gene Expression

Tunstall, Rebecca J, McAinch, Andrew, Hargreaves, Mark, van Loon, Luc J.C and Cameron-Smith, David (2007) Reduced Plasma Free Fatty Acid Availability During Exercise: Effect on Gene Expression. European Journal of Applied Physiology, 99 (5). pp. 485-493. ISSN 1439-6319

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Abstract

Endurance exercise transiently increases the mRNA of key regulatory proteins involved in skeletal muscle metabolism. During prolonged exercise and subsequent recovery, circulating plasma fatty acid (FA) concentrations are elevated. The present study therefore aimed to determine the sensitivity of key metabolic genes to FA exposure, assessed in vitro using L6 myocytes and secondly, to measure the expression of these same set of genes in vivo, following a single exercise bout when the post-exercise rise in plasma FA is abolished by acipimox. Initial studies using L6 myotubes demonstrated dose responsive sensitivity for both PDK4 and PGC-1α mRNA to acute FA exposure in vitro. Nine active males performed two trials consisting of 2 h exercise, followed by 2 h of recovery. In one trial, plasma FA availability was reduced by the administration of acipimox (LFA), a pharmacological inhibitor of adipose tissue lipolysis, and in the second trial a placebo was provided (CON). During the exercise bout and during recovery, the rise in plasma FA and glycerol was abolished by acipimox treatment. Following exercise the mRNA abundance of PDK4 and PGC-1α were elevated and unaVected by either acipimox or placebo. Further analysis of skeletal muscle gene expression demonstrated that the CPT I gene was suppressed in both trials, whilst UCP-3 gene was only modestly regulated by exercise alone. Acipimox ingestion did not alter the response for both CPT I and UCP-3. Thus, this study demonstrates that the normal increase in circulating concentrations of FA during the later stages of exercise and subsequent recovery is not required to induce skeletal muscle mRNA expression of several proteins involved in regulating substrate metabolism.

Item Type: Article
Uncontrolled Keywords: ResPubID14437, mRNA expression, lipolysis, muscle metabolism, endurance exercise, fatty acids, FA, gene transcription, nicotinic acid ingestion, FA-sensitive transcriptional pathways, maximum work-load, Wmax, VO2max, maximum oxygen uptake, exercise intervention
Subjects: Faculty/School/Research Centre/Department > School of Biomedical and Health Sciences
FOR Classification > 1101 Medical Biochemistry and Metabolomics
FOR Classification > 1102 Cardiorespiratory Medicine and Haematology
FOR Classification > 1106 Human Movement and Sports Science
Depositing User: Yimin Zeng
Date Deposited: 09 May 2013 04:39
Last Modified: 08 Aug 2013 07:33
URI: http://vuir.vu.edu.au/id/eprint/21496
DOI: https://doi.org/10.1007/s00421-006-0376-5
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Citations in Scopus: 19 - View on Scopus

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