2000 Fiscal Year Final Research Report Summary
Possible role of adipocytokines in exercise-induced improvement of obesity and insulin-resistance.
| Project/Area Number |
11680044
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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 | Tokyo Metropolitan University |
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Principal Investigator |
IZAW Tetsuya Tokyo Metropolitan Univ, Kinesiology, Professor, 理学研究科, 教授 (70147495)
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| Project Period (FY) |
1999 – 2000
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| Keywords | rat / adipocytes / adipocyte lipolysis / TNF-α / TNF-α receptor / cyclooxygenase |
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| Research Abstract |
This research project examined possible role of adipocytokines in exercise-induced improvement of obesity and insulin-resistance. The increase in plasma concentrations of tumor necrosis factor (TNF)- α has been shown to result in insulin resistance. It is unclear, however, whether endurance exercise training can reduce the ability of adipocytes to secrete TNF- α. Therefore, we examined the effects of endurance training on the secretions of TNF- α and soluble TNF- α receptor (sTNFR) from isolated adipocytes. The expressions of menbrane-p55 TNF receptor (TNFR) in adipocytes were also examined. Male Wistar rats were divided into two groups, sedentary control and exercise-trained group. The rats of exercise-trained group were exercised on a rodent treadmill for 9 weeks. Adipocytes were isolated from the epididymal adipose tissue at least 36 hours after the last bout of exercise. The adipocytes (250000 per tube) were incubated in 5ml of DMEM/Ham's F12 medium for 24 hours at 37℃. The amounts of TNF- α and sTNFR in the culture medium were measured by ELISA.TNFR was measured by Western blot analysis. Exercise training increased significantly the secretions of TNF- α from isolated adipocytes. This increase was completely blocked by indomethacin or ETYA, cyclooxygenase inhibitors, suggesting that the enhanced secretions could be mediated by a possible change in the activity of cyclooxygenase. On the other hand, exercise training could decrease the secretions of sTNFR.The concentrations of sTNFR tended to be less in exercise-trained than in control rats. In contrast, exercise training could increase the expressions of TNFR proteins in adipocytes. This result suggests that TR would enhance the autocrine effect of TNF- α on adipocytes.
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