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Long‐term Exercise Intervention Ameliorates Vasorelaxation Mediated by Insulin and Insulin‐like Growth Factor‐1 in Aortas of Diabetic Rats
Author(s) -
Fu KengYeh,
Su ChiaTing,
Yang AiLun
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1226.3
Subject(s) - medicine , insulin , endocrinology , sodium nitroprusside , diabetes mellitus , streptozotocin , nitric oxide synthase , isometric exercise , nitric oxide
In order to investigate whether exercise ameliorates insulin‐ and insulin‐like growth factor‐1 (IGF‐1)‐mediated vasorelaxation in the diabetes, male Wistar rats were randomly divided into non‐diabetic control (Con), diabetic control (DM), and diabetes with exercise (DM+Ex) groups. Diabetic groups were induced by the intravenous injection of streptozotocin. The DM+Ex group performed an 8‐week treadmill exercise program for 60 min/day, 5 day/week. At the end of experiments, the vasorelaxant responses to insulin, IGF‐1, acetylcholine (ACh), and sodium nitroprusside (SNP) were evaluated by the isometric tension of aortic rings in the organ baths. In addition, the roles of phosphatidylinositol 3‐kinase (PI3‐K) and nitric oxide synthase (NOS) in the vasorelaxation were examined by treating selective inhibitors. We found that 1) insulin‐, IGF‐1‐, and ACh‐induced vasorelaxant responses were significantly impaired in the DM group, compared with those in the Con group ( P <0.05); 2) the exercise intervention significantly ameliorated the impaired vascular responses to insulin, IGF‐1, and ACh in the DM+Ex group, compared with those in the DM group ( P <0.05); 3) these alternations of vascular responses affected by diabetes and exercise were mainly due to the release of PI3‐K and NOS; 4) no significant difference was found in SNP‐induced vasorelaxation among the three groups. Our results suggest that long‐term exercise intervention ameliorates vasorelaxation mediated by insulin and IGF‐1 in type 1 diabetic rats. The PI3K‐NOS‐dependent pathway is mainly involved in the exercise‐induced beneficial effects. This study was partly supported by the National Science Council, Taiwan (NSC95‐2314‐B‐006‐073‐MY2).