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Acute exercise induces biphasic increase in respiratory mRNA in skeletal muscle
Shin-ichi Ikeda1, Takako Kizaki, Shukoh Haga
1Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8574, Japan.
Abstract:
Peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) promotes the expression of oxidative enzymes in skeletal muscle. We hypothesized that activation of the p38 MAPK (mitogen-activated protein kinase) in response to exercise was associated with exercise-induced PGC-1alpha and respiratory enzymes expression and aimed to demonstrate this under the physiological level. We subjected mice to a single bout of treadmill running and found that the exercise induced a biphasic increase in the expression of respiratory enzymes mRNA. The second phase of the increase was accompanied by an increase in PGC-1alpha protein, but the other was not. Administration of SB203580 (SB), an inhibitor of p38 MAPK, suppressed the increase in PGC-1alpha expression and respiratory enzymes mRNA in both phases. These data suggest that p38 MAPK is associated with the exercise-induced expression of PGC-1alpha and biphasic increase in respiratory enzyme mRNAs in mouse skeletal muscle under physiological conditions.
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