Effects of Long-term Exercise Training and Insulin Treatment on Insulin- and Insulin-like Growth Factor-1-mediated Vascular Function in Type 1 Diabetic Rats
| Autor: | Keng-Yeh Fu, 傅耕業 |
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| Rok vydání: | 2008 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 96 Background and Purpose: Insulin and insulin-like growth factor-1 (IGF-1) have potent vasorelaxation effect via the production of endothelium-derived nitric oxide (EDNO). Accumulating evidences have indicated that both exercise training and insulin treatment improve vascular function by increasing EDNO bioavailability. However, few studies focus on the effects of these interventions on vascular responses mediated by insulin and IGF-1 in type 1 diabetic status. Therefore, the aim of the present study was to investigate the effects of long-term exercise training and insulin treatment on insulin- and IGF-1-mediated vascular function in type 1 diabetic status. Methods: Male Wistar rats were randomly divided into the non-diabetic control (Con), the diabetic (DM), the diabetes with exercise training (DM+Ex), and the diabetes with insulin treatment (DM+IT) groups. Type 1 diabetes mellitus was induced by the intravenous injection of streptozotocin (65 mg/kg). The DM+Ex group performed an 8-week, moderate-intensity treadmill exercise program for 60 min/day, 5 day/week. The DM+IT group received a daily insulin treatment for 8 weeks with the gradually increased dose from 20 to 40 U/kg/day. At the end of experiments, the vasorelaxation responses to insulin, IGF-1, acetylcholine (ACh), and sodium nitroprusside (SNP) in thoracic aortas were evaluated among four groups. In addition, the roles of phosphatidylinositol 3-kinase (PI3-K) and endothelial NO synthase (eNOS) in the vasorelaxation responses were examined. Results: We found that 1) insulin- and IGF-1-mediated vasorelaxation was significantly impaired in the DM group compared with that in the Con group (P |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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