| Budget Amount *help |
¥14,800,000 (Direct Cost: ¥14,800,000)
Fiscal Year 2005: ¥7,200,000 (Direct Cost: ¥7,200,000)
Fiscal Year 2004: ¥7,600,000 (Direct Cost: ¥7,600,000)
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| Research Abstract |
First, we measured peroxisome proliferator-activated receptor γ coactivator-1 α(PGC-1 α) protein content in the skeletal muscles of male SD rats (age : 5-6 weeks old) after a single session of high-intensity intermittent exercise (HIE) or low-intensity prolonged swimming exercise (LIE). During HIE, the rats swam for fourteen 20-second periods carrying a weight (14% of body weight), and the periods of swimming were separated by a 10-s pause. LIE rats swam with no load for 6 hours in two 3-h sessions, separated by 45 minutes of rest. After HIE, the PGC-1 α protein content in rat epitrochlearis (EPI) muscle had increased by 126, 140, and 126 % at 2h, 6h, and 18h, respectively, compared with that of the control rats. Immediately, 6h, and 18-h after LIE, the PGC-1 α protein content in the muscle was significantly elevated by 84, 95, and 67%, respectively. However, there was no statistically significant difference between the two values.
To elucidate dose-response relationship between number
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of exercise bouts during training and training-induced expression of PGC-1α, GLUT-4, and mitochondrial proteins in rat skeletal muscle. In year 2005, Thirty two 5-w old SD rats were randomly assigned to a control group and three exercise training groups. Five days swimming training consisted of three (HIT3), or seven (HIT7), or fourteen (HIT14) bouts of 20-s high-intensity swimming exercise with 10-s pause between the exercise bouts. As a result, the GLUT-4 protein content in rat EPI muscle increased by 75, 83, and 71%, 18-hour after the last session of HIT3, HIT7, and HIT14, respectively, compared with the control rats' muscle. Citrate synthase activity in the muscle was elevated by 23 (HIT3), 23 (HIT7) and 25% (HIT14). There were no significant differences in neither GLUT-4 nor citrate synthase activity among the three training groups. The protein content of PGC-1α was also 61 (HIT3), 43 (HIT7), and 22% (HIT14) higher than the control values.
In conclusion, the present investigation suggests that irrespective of the intensity and duration (set) of the exercise training, PGC-1α, GLUT-4, and citrate synthase protein content in rat skeletal muscle increases to a comparable level when stimuli induced by different protocols are saturated. Less
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