Exercise training improves insulin-induced and insulin-like growth factor-1-induced vasorelaxation in rat aortas.
Improved vasorelaxant response is one of the beneficial effects of exercise training on vascular function. The mechanism for this response is, however, poorly understood. The aim of this study was to investigate the effects of exercise training on insulin-induced and insulin-like growth factor-1 (IGF-1)-induced vasorelaxation. Fourteen 6-week-old male Wistar rats were randomly divided into sedentary control and exercise groups. For 12 weeks, the exercise group ran on a treadmill 60 min/day, 5 days/week. After exercise training, insulin-induced and IGF-1-induced vasorelaxant responses were evaluated by measuring the isometric tension of aortic rings. The vasorelaxant role of phosphatidylinositol 3-kinase (PI3K) and nitric oxide synthase (NOS) was examined by applying inhibitors, such as wortmannin (an inhibitor of PI3K) and N(omega)-nitro-L-arginine methyl ester (L-NAME, a NOS inhibitor). In addition, we examined the vascular response to the NO donor, sodium nitroprusside (SNP). We found that: (1) exercise training significantly enhanced both insulin-induced and IGF-1-induced vasorelaxation in rat aortas; (2) this vasorelaxant effect disappeared after the use of wortmannin or L-NAME; (3) there was no significant difference in SNP-induced vasorelaxation between control and exercise groups. Our findings indicate that exercise training enhances insulin-induced and IGF-1-induced vasorelaxant responses which are mediated through the PI3K-NOS-dependent pathway.
Yang
Ai-Lun
AL
Department of Physical Therapy, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Su
Chia-Ting
CT
Lin
Ko-Long
KL
Chao
Jung-I
JI
You
Huei-Ping
HP
Lee
Shin-Da
SD
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000502:physiology; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051381:Rats; D017208:Rats, Wistar; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects* / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology
D004791:Enzyme Inhibitors; D007328:Insulin; D007334:Insulin-Like Growth Factor I; D019001:Nitric Oxide Synthase; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents