Enhancement of Vascular Function Mediated by Insulin and Insulin-like Growth Factor-1 Following Single Exercise Session

Ai-Lun Yang ； Chia-Ting Su ； Ko-Long Lin ； Shin-Da Lee

《The Chinese Journal of Physiology》 51卷2期 (2008/04) Pp. 71-77

並列摘要

Exercise is well known to improve vascular functions, but the underlying mechanism has not been totally understood. The aim of this study was to examine whether single exercise session acutely enhances insulin-induced and insulin-like growth factor-1 (IGF-1)-induced vasorelaxation. Twenty-four male Wistar rats at age of 12 weeks were randomly divided into two groups, control (n=12) and exercise (n=12) group. The exercise group ran on a treadmill at a speed of 18 m/min for 60 min. Immediately after exercise, insulin-induced and IGF-1-induced vasorelaxant responses were evaluated by the isometric tension of aortic rings in the organ baths. The roles of phosphatidylinositol 3-kinase (PI3K) and nitric oxide synthase (NOS) in vasorelaxant responses were examined by treating selective inhibitors, such as wortmannin (an inhibitor of PI3K) and N(superscrip ω)-nitro-L-arginine methyl ester (L-NAME, a NOS inhibitor). In addition, the vascular responses to sodium nitroprusside (SNP), a NO donor, were examined. We found that single exercise session significantly enhanced vasorelaxation mediated by insulin and IGF-1 in rat aortas (P ＜ 0.01). Also, the exercise-enhanced vasorelaxation was abolished by wortmannin or L-NAME. There was no significant difference of SNP-induced vasorelaxation between control and exercise groups. These results indicate that single exercise session acutely enhances insulininduced and IGF-1-induced vasorelaxation through the PI3K-NOS-dependent pathway.

並列關鍵字

exercise ； aortas ； insulin ； insulin-like growth factor-1 ； nitric oxide

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