title: Enhancement of vascular function mediated by insulin and insulin-like growth factor-1 following single exercise session.
abstract: Exercise is well-known in improving 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(omega)-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 insulin-induced and IGF-1-induced vasorelaxation through the PI3K-NOS-dependent pathway.
authors.affiliation: Department of Physical Therapy, National Cheng Kung University, Tainan, Taiwan, Republic of China.
authors.forename: Ai-Lun
authors.initials: AL
authors.lastname: Yang
authors.forename: Chia-Ting
authors.initials: CT
authors.lastname: Su
authors.forename: Ko-Long
authors.initials: KL
authors.lastname: Lin
authors.forename: Shin-Da
authors.initials: SD
authors.lastname: Lee
mesh_terms: D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000502:physiology; D009599:Nitroprusside / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013002:Somatomedins / Q000494:pharmacology*; D014664:Vasodilation / Q000187:drug effects*; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D007328:Insulin; D013002:Somatomedins; D009599:Nitroprusside; D019001:Nitric Oxide Synthase; D019869:Phosphatidylinositol 3-Kinases; D019331:NG-Nitroarginine Methyl Ester; D000077191:Wortmannin