Ang II attenuates IGF-1-stimulated Na+, K(+)-ATPase activity via PI3K/Akt pathway in vascular smooth muscle cells.

We have investigated the role of phosphatidylinositol 3-kinase (PI3K) and serine/threonine protein kinase B (Akt) in mediating vascular smooth muscle cells (VSMC) sodium pump (Na+, K(+)-ATPase) regulatory interactions between insulin-like growth factor-1 (IGF-1) and angiotensin II (Ang II). Treatment with IGF-1 (100 nM) for 30 min or Ang II (100 nM) for 10 min increased sodium pump activity. Pretreatment with Ang II for 10 min, abolished IGF-1 increased sodium pump activity.

Angiotensin II regulation of the Na+ pump involves the phosphatidylinositol-3 kinase and p42/44 mitogen-activated protein kinase signaling pathways in vascular smooth muscle cells.

This investigation used primary cultured rat vascular smooth muscle cells to examine angiotensin II (Ang II) regulation of Na(+), K(+)-ATPase (Na(+) pump) activity, and Na(+) pump alpha(1)- and beta(1)-subunit gene transcription. This regulation was mediated through both phosphatidylinositol-3 kinase (PI3K) and p42/44 mitogen-activated protein kinase (p42/44(MAPK)) signaling pathways. Both acute (10 min) and prolonged (24 h) treatment with Ang II stimulated Na(+) pump activity.

Interactive effects of insulin-like growth factor-1 and beta-estradiol on endothelial nitric oxide synthase activity in rat aortic endothelial cells.

Insulin-like growth factor-1 (IGF-1) and beta-estradiol (E2) have vasodilatory effects, in part, through stimulation of vascular nitric oxide (NO) production. However, their interactive effects on endothelial nitric oxide synthase (eNOS) and NO production have not been previously studied in endothelial cells (EC). Employing rat aortic EC (RAEC), the effects of acute (20 and 30 minutes) and prolonged (4 hours) stimulation with 100 nmol/L IGF-1 and 1 nmol/L E2 (alone or in combination) were assessed with respect to protein levels and enzymatic activities for phosphatidyl inositol 3-kinase (PI3K) and serine/threonine kinase Akt (Akt), enzymes involved in eNOS activation.

Role of phosphatidylinositol 3-kinase/Akt pathway in angiotensin II and insulin-like growth factor-1 modulation of nitric oxide synthase in vascular smooth muscle cells.

The aim of this study was to examine the role of the phosphatidylinositol 3-kinase (PI3K)/serine/threonine kinase Akt signaling pathway in mediating interactions between angiotensin II (Ang II) and insulin-like growth factor-1 (IGF-1) in regulation of inducible nitric oxide synthase (iNOS) in vascular smooth muscle cells (VSMCs). Exposure to 100 nM IGF-1 for 10 min resulted in increased insulin-receptor substrate-1 associated PI3K activity and Akt kinase activity, whereas 100 nM Ang II pretreatment for 5 min strikingly decreased these IGF-1 effects. NOS activity was also increased in VSMCs following exposure to IGF-1 (10 min up to 24 h).