Review Vascular actions of insulin with implications for endothelial dysfunction

dynamic actions of insulin depend largely on the hormone’s ability to stimulate synthesis and release of endothelial mediators, whose balanced activity ensures dynamic control of vascular function. Nitric oxide (NO), endothelin-1 (ET-1), and reactive oxygen species (ROS) are important examples of endothelial mediators with opposing properties on vascular tone, hemostatic processes, and vascular permeability. Reduced NO bioavailability, resulting from either insufficient pro-duction or increased degradation of NO, characterizes endothelial dysfunction. In turn, endothelial dysfunction predicts vascular complications of metabolic and hemodynamic disorders. In the cardiovascular system, insulin stimulates the pro-duction and release of NO, ET-1, and ROS via activation of distinct intracellular signaling pathways. Under insulin-resistant conditions, increased insulin concen-trations and/or impaired insulin-signaling pathways in the vasculature may con-tribute to imbalance in secretion of endothelial mediators that promote pathogenesis of vascular abnormalities. This short review describes signaling pathways involved in insulin-stimulated release of NO, ROS, and ET-1 and suggests possible molec