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Effect of sex differences on human MEF2 regulation during endurance exercise
journal contribution
posted on 2008-02-01, 00:00 authored by K Vissing, Sean McgeeSean Mcgee, C Roepstorff, P Scherling, Mark Hargreaves, B KiensWomen exhibit an enhanced capability for lipid metabolism during endurance exercise compared with men. The underlying regulatory mechanisms behind this sex-related difference are not well understood but may comprise signaling through a myocyte enhancer factor 2 (MEF2) regulatory pathway. The primary purpose of this study, therefore, was to investigate the protein signaling of MEF2 regulatory pathway components at rest and during 90 min of bicycling exercise at 60% VO2peak in healthy, moderately trained men (n = 8) and women (n = 9) to elucidate the potential role of these proteins in substrate utilization during exercise. A secondary purpose was to screen for mRNA expression of MEF2 isoforms and myogenic regulatory factor (MRF) family members of transcription factors at rest and during exercise. Muscle biopsies were obtained before and immediately after exercise. Nuclear AMP-activated protein kinase-{alpha} ({alpha}AMPK) Thr172 (P < 0.001), histone deacetylase 5 (HDAC5) Ser498 (P < 0.001), and MEF2 Thr (P < 0.01) phosphorylation increased with exercise. No significant sex differences were observed at rest or during exercise. At rest, no significant sex differences were observed in mRNA expression of the measured transcription factors. mRNA for transcription factors MyoD, myogenin, MRF4, MEF2A, MEF2C, MEF2D, and peroxisome proliferator-activated receptor-{gamma} coactivator 1{alpha} (PGC1{alpha}) were significantly upregulated by exercise. Of these, MEF2A mRNA increased 25% specifically in women (P < 0.05), whereas MEF2D mRNA tended to increase in men (P = 0.11). Although minor sex differences in mRNA expression were observed, the main finding of the present study was the implication of a joint signaling action of AMPK, HDAC5, and PGC1{alpha} on MEF2 in the immediate regulatory response to endurance exercise. This signaling response was independent of sex.
History
Journal
American journal of physiology : endocrinology and metabolismVolume
294Issue
2Pagination
408 - 415Publisher
American Physiological SocietyLocation
Bethesada, Md.Publisher DOI
ISSN
0193-1849eISSN
1522-1555Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
2008, American Physiological SocietyUsage metrics
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No categories selectedKeywords
Science & TechnologyLife Sciences & BiomedicineEndocrinology & MetabolismPhysiologyskeletal musclemyogenic regulatory factorAMP-activated protein kinasehistone deacetylase 5peroxisome proliferator-activated receptor-gamma coactivator 1 alphaHUMAN SKELETAL-MUSCLETRANSCRIPTION FACTORGAMMA COACTIVATOR-1GENE-EXPRESSIONPROTEIN-KINASEACTIVATIONGENDERWOMENAMPKP38
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