Insulin rapidly stimulates L-arginine transport in human aortic endothelial cells via Akt.

Insulin stimulates endothelial NO synthesis, at least in part mediated by phosphorylation and activation of endothelial NO synthase at Ser1177 and Ser615 by Akt. We have previously demonstrated that insulin-stimulated NO synthesis is inhibited under high culture glucose conditions, without altering Ca(2+)-stimulated NO synthesis or insulin-stimulated phosphorylation of eNOS. This indicates that stimulation of endothelial NO synthase phosphorylation may be required, yet not sufficient, for insulin-stimulated nitric oxide synthesis.