Acute endurance exercise increases skeletal muscle uncoupling protein-3 gene expression in untrained but not trained humans.
In rodents, acute exercise increases skeletal muscle uncoupling protein (UCP) gene expression and is associated with elevations in serum nonesterified fatty acids (NEFA). To test whether contractions increase UCP mRNA levels in humans, vastus lateralis biopsies were obtained 1 hour postexercise from untrained and trained subjects and analyzed for UCP-2 and UCP-3 long (UCP-3(L)) and short (UCP-3(S)) isoforms. The acute exercise bout (graded cycling protocol; 65% to 85% relative VO(2)max) induced significant (P <.01) elevations in serum NEFA in both untrained and trained subjects, but the increase in untrained subjects was significantly (P <.05) greater (60% v 30%). Ribonuclease protection assay demonstrated that basal levels of all UCP isoforms measured were similar between the 2 groups. However, acute exercise induced a significant increase (P <.02) in both UCP-3(L) and UCP-3(S), but not UCP-2 mRNA levels in untrained, but not trained subjects. Correlation analysis did not show a significant relationship between exercise-induced changes in NEFA and UCP-3 levels. These results demonstrate that acute endurance exercise increases UCP-3 gene expression only in untrained skeletal muscle, but this effect does not seem to be tightly linked to the exercise-induced fluctuations in serum NEFA levels.
Noland
Robert C
RC
Department of Exercise and Sport Science (Human Performance Laboratory), Brody School of Medicine, East Carolina University, Greenville, NC 27858, USA.
Hickner
Robert C
RC
Jimenez-Linan
Mercedes
M
Vidal-Puig
Antonio
A
Zheng
Donghai
D
Dohm
G Lynis
GL
Cortright
Ronald N
RN
D000328:Adult; D001642:Bicycling / Q000502:physiology; D001769:Blood / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics*; D015444:Exercise / Q000502:physiology*; D005260:Female; D015870:Gene Expression; D006801:Humans; D007473:Ion Channels; D008297:Male; D024101:Mitochondrial Proteins; D018482:Muscle, Skeletal / Q000502:physiology*; D010806:Physical Education and Training; D010807:Physical Endurance; D012333:RNA, Messenger / Q000378:metabolism; D000071247:Uncoupling Protein 3
D002352:Carrier Proteins; D007473:Ion Channels; D024101:Mitochondrial Proteins; D012333:RNA, Messenger; C000604392:UCP3 protein, human; D000071247:Uncoupling Protein 3