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Med Sci Sports Exerc. 2010 Aug;42(8):1477-84. doi: 10.1249/MSS.0b013e3181d2d21c.

Relative workload determines exercise-induced increases in PGC-1alpha mRNA.

Author information

1
Copenhagen Muscle Research Centre, University of Copenhagen, Denmark. nnordsborg@ifi.ku.dk

Abstract

INTRODUCTION:

The hypothesis that brief intermittent exercise-induced increases in human skeletal muscle metabolic mRNA is dependent on relative workload was investigated.

METHODS:

Trained (n = 10) and untrained (n = 8) subjects performed exhaustive intermittent cycling exercise (4 x 4 min at 85% of VO(2peak), interspersed by 3 min). Trained subjects also performed the intermittent exercise at the same absolute workload as the untrained subjects, corresponding to 70% of VO(2peak) (n = 6).

RESULTS:

Exercise at 85% of V(O2peak) elevated (P < 0.001) venous plasma lactate to 10.1 +/- 0.4 and 10.8 +/- 0.5 mM in the trained and untrained subjects, respectively. Peroxisome proliferator-activated receptor gamma coactivator 1alpha (PGC-1alpha) mRNA expression was increased (P < 0.001) approximately four- to fivefold for several hours after exercise in both groups. After exercise at 70% of VO(2peak), venous plasma lactate was less (P < 0.001) elevated (3.1 +/- 0.7 mM) and PGC-1alpha mRNA content was less (P < 0.05) increased (approximately threefold) than after exercise at 85% of VO(2peak). Likewise, pyruvate dehydrogenase kinase 4 and hexokinase II mRNA expressions were increased (P < 0.05) only after exercise performed at 85% of VO(2peak) in the trained subjects. Hypoxia-inducible factor 2alpha mRNA only increased (P < 0.05) 3 h into recovery in trained subjects, with no difference between the 70% and 85% of VO(2peak) trial. No change in hypoxia-inducible factor 1alpha, phosphofructokinase, citrate synthase, or lactate dehydrogenase, heart and muscle isoforms, mRNA expressions was detected after any of the exercise trials.

CONCLUSIONS:

The relative intensity of brief intermittent exercise is of major importance for the exercise-induced increase of several mRNA, including PGC-1alpha.

PMID:
20139785
DOI:
10.1249/MSS.0b013e3181d2d21c
[Indexed for MEDLINE]

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