Effects of low-intensity prolonged exercise on PGC-1 mRNA expression in rat epitrochlearis muscle

S Terada, M Goto, M Kato, K Kawanaka… - Biochemical and …, 2002 - Elsevier
S Terada, M Goto, M Kato, K Kawanaka, T Shimokawa, I Tabata
Biochemical and biophysical research communications, 2002Elsevier
We previously reported that the peroxisome proliferator-activated receptor γ coactivator-1
(PGC-1) mRNA in rat epitrochlearis muscle was increased after swimming exercise training.
In the present study, we demonstrated further that PGC-1 mRNA expression in the
epitrochlearis muscle of 4–5-week-old male Sprague–Dawley rats was increased after a 6-h
acute bout of low-intensity swimming exercise. With this increase, the expression level was
approximately 8-fold of control and immersion group rats that stayed for 6-h in warm water …
We previously reported that the peroxisome proliferator-activated receptor γ coactivator-1 (PGC-1) mRNA in rat epitrochlearis muscle was increased after swimming exercise training. In the present study, we demonstrated further that PGC-1 mRNA expression in the epitrochlearis muscle of 4–5-week-old male Sprague–Dawley rats was increased after a 6-h acute bout of low-intensity swimming exercise. With this increase, the expression level was approximately 8-fold of control and immersion group rats that stayed for 6-h in warm water, maintained at the identical temperature of the swimming barrel (35°C) (p<0.01). Second, PGC-1 mRNA expression in the muscle was found to have increased 6-h after 30 10-s tetani contractions were induced by in vitro electrical stimulation. Finally, PGC-1 mRNA expression in the muscle incubated for 18-h with 0.5mM 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR: a 5 AMP-activated protein kinase (AMPK) activator) was elevated to approximately 3-fold of the control muscle (n=6, p<0.001). AMPK activity in epitrochlearis muscle after the swimming was also found to be elevated to approximately 4-fold of the pre-exercise value (p<0.001). These results may suggest that an acute bout of low-intensity prolonged swimming exercise directly enhances the PGC-1 mRNA expression in the activated muscle during exercise, possibly through, at least in part, an AMPK-related mechanism.
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