Effects of low-intensity prolonged exercise on PGC-1 mRNA expression in rat epitrochlearis muscle.
We previously reported that the peroxisome proliferator-activated receptor gamma 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 degrees 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.
Terada
Shin
S
Laboratory of Exercise Physiology, National Institute of Health and Nutrition, 1-23-1 Toyama, Shinjuku City, Tokyo, Japan.
Goto
Masahide
M
Kato
Miyuki
M
Kawanaka
Kentaro
K
Shimokawa
Teruhiko
T
Tabata
Izumi
I
D055372:AMP-Activated Protein Kinases; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D004558:Electric Stimulation; D004789:Enzyme Activation; D066298:In Vitro Techniques; D008297:Male; D009097:Multienzyme Complexes / Q000378:metabolism; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism*; D010805:Physical Conditioning, Animal; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012263:Ribonucleosides / Q000494:pharmacology; D013550:Swimming; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D009097:Multienzyme Complexes; D012263:Ribonucleosides; D014157:Transcription Factors; C111264:peroxisome-proliferator-activated receptor-gamma coactivator-1; D000620:Aminoimidazole Carboxamide; C011651:acadesine; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases