2003 Fiscal Year Final Research Report Summary
EFFECTS OF PHYSICAL TRAINING-INDUCED SKELETALMUSCLE TRANSCRIPTIONAL ACTIVAIONS ON GLUCOSE METABOLISM
| Project/Area Number |
14580046
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
体育学
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| Research Institution | National Institute of Health and Nutrition |
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Principal Investigator |
TABATA Izumi National Institute of Health and Nutrition, Division of Health Promotion and Exercise, Division Chief, 健康増進研究部, 室長 (20188402)
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| Project Period (FY) |
2002 – 2003
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| Keywords | PGC-1 / Swimming exercise / Running exercise / AMPK / AICAR / Epitrochlearis / Soleus / ヒラメ筋 |
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| Research Abstract |
The purpose of this study was to elucidate the mechanisms underlying low-intensity-exercise-induced peroxisome proliferator-activated receptor γ coactivator-1 α (PGC-1 α) protein expression in rat skeletal muscles. Rats (5-6-week-old) swam without a load and ran on the treadmill at a speed of 13 m/min, respectively, in two 3-h sessions separated by 45 min of rest. PGC-1 α content in epitrochlearis muscle (EPI) was increased by 75 % and 95 %, immediately and 6-h post-swimming, respectively, with no increase in PGC-1 α content in the soleus (SOL). After running, PGC-1 α content in EPI was unchanged, while a 107 % increase in PGC- 1 α content was observed in SOL 6-h post-running. Furthermore, in EPI and SOL as well as other muscles (triceps, plantaris, red and white gastrocnemius), PGC-1 α expression was enhanced concomitant with reduced glycogen post-exercise, suggesting that expression of PGC-1 α occurs in skeletal muscle recruited during exercise.
Six-hour after in vitro electrical stimulation, mRNA of PGC-1 α increased in epitrochlearis muscle dissected from sedentary rat. PGC-1 α content in EPI was increased after 18-h in vitro incubation with 0.5 mM 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) and 4 mM caffeine. However, AICAR incubation did not affect PGC-1 α content in the SOL, while PGC-1 α content in the SOL was increased after caffeine incubation. These results suggest that exercise-induced PGC-1 α expression in skeletal muscle may mediated by at least two exercise-induced signaling factors : AMPK activation and Ca2+ elevation. The number of factors involved (both AMPK and Ca2+, or Ca2+ only) in exercise-induced PGC-1 α expression may differ among muscles.
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