Role of PI3-kinase in isoproterenol and IGF-1 induced ecNOS activity

E Isenović, R Muniyappa, N Milivojević, Y Rao… - Biochemical and …, 2001 - Elsevier
E Isenović, R Muniyappa, N Milivojević, Y Rao, JR Sowers
Biochemical and Biophysical Research Communications, 2001Elsevier
Phosphatidylinositol 3-kinase (PI3-K) has been shown to mediate insulin and insulin-like
growth factor-1 (IGF-1)-induced nitric oxide (NO) generation and, thus, vascular tone. A role
for PI3-K in G-protein-coupled receptor signal transduction has been reported. As beta (β2)-
adrenergic vascular actions are partly dependent on NO, we have investigated the role of
PI3-K in isoproterenol (Iso) and IGF-1 induced endothelial NO synthase (ecNOS) activity in
rat aortic endothelial cells (RAEC). Cell lysates of RAEC, exposed to Iso (10 μmol/L) for 5 …
Phosphatidylinositol 3-kinase (PI3-K) has been shown to mediate insulin and insulin-like growth factor-1 (IGF-1)-induced nitric oxide (NO) generation and, thus, vascular tone. A role for PI3-K in G-protein-coupled receptor signal transduction has been reported. As beta (β2)-adrenergic vascular actions are partly dependent on NO, we have investigated the role of PI3-K in isoproterenol (Iso) and IGF-1 induced endothelial NO synthase (ecNOS) activity in rat aortic endothelial cells (RAEC). Cell lysates of RAEC, exposed to Iso (10 μmol/L) for 5 min and 6 h, and to IGF-1 (100 nM) for 10 min and 6 h, or pretreated with PI3-K inhibitor Wortmannin (WT), were used for measuring PI3-K activity, p85kDa regulatory protein, and citrulline production. Results show that Iso and IGF-1 increased a p85 subunit and citrulline production, and also enhanced 32P incorporation into PIP3. Pretreatment with WT inhibited Iso-stimulated ecNOS, as well as, PI3-K activity. Iso enhanced association of ecNOS with the triton X-100-insoluble fraction of RAEC. These data indicate that the endothelial cell PI3-K pathway mediates, in part, the release of NO and subsequent vasorelaxation in response to this β-agonist, as well as, IGF-1.
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