Muscle type-specific response of PGC-1 alpha and oxidative enzymes during voluntary wheel running in mouse skeletal muscle.
OBJECTIVE
It is generally accepted that endurance exercise increases the expression of peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha), which governs the expression of oxidative metabolic enzymes. A previous report demonstrated that the regulation of mitochondrial protein expression in skeletal muscles in response to cold exposure depends on muscle fibre type. Cold exposure and endurance exercise are both metabolic challenges that require adjustments in mitochondrial energy metabolism, we hypothesized that the exercise-induced increase in oxidative enzymes and PGC-1alpha expression is higher in fast-type than in slow-type muscle.


METHODS
Female ICR mice were individually housed in cages equipped with running wheel for 1, 2, 4, 6 or 8 weeks. The soleus, plantaris (PLA) and tibialis anterior (TA) muscles were then prepared from each mouse. The expression levels of PGC-1alpha, mitochondrial proteins and GLUT4 were evaluated by Western blotting.


RESULTS
The expression level of PGC-1alpha was increased only in the PLA muscle. Furthermore, the expression levels of all mitochondrial proteins and GLUT4 in the PLA muscle were increased. In the TA muscle, although there was no increase in PGC-1alpha expression, the expression levels of mitochondrial proteins and GLUT4 were increased.


CONCLUSIONS
These results suggest that muscle type-specific responses occur during endurance exercise, and that the increase in PGC-1alpha expression is not the only factor that promotes oxidative capacity as a result of endurance exercise.
Ikeda
S
S
Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan.
Kawamoto
H
H
Kasaoka
K
K
Hitomi
Y
Y
Kizaki
T
T
Sankai
Y
Y
Ohno
H
H
Haga
S
S
Takemasa
T
T
D000818:Animals; D001835:Body Weight / Q000502:physiology; D005260:Female; D051275:Glucose Transporter Type 4 / Q000032:analysis; D051379:Mice; D008813:Mice, Inbred ICR; D024101:Mitochondrial Proteins / Q000032:analysis; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000201:enzymology / Q000378:metabolism*; D010084:Oxidation-Reduction; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D010805:Physical Conditioning, Animal / Q000502:physiology*; D010807:Physical Endurance; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors
D051275:Glucose Transporter Type 4; D024101:Mitochondrial Proteins; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C485290:Ppargc1a protein, mouse; C495693:Slc2a4 protein, mouse; D015534:Trans-Activators; D014157:Transcription Factors