Endothelium-derived vasoactive factors and the renal vasculature.

The endothelium is now recognized to transduce intravascular hemodynamic and chemical signals into appropriate changes in vascular smooth muscle (VSM) tone. The effector branch of this transduction is due, at least in part, to endothelial release of potent soluble vasoactive mediators. Two such mediators, endothelium-derived relaxing factor (EDRF) and endothelin, have markedly different chemical composition and contrasting effects on VSM tone. EDRF, identified to be nitric oxide or a nitrosothiol, is a vasodilator, whereas endothelin, a 21-amino acid polypeptide, is the most potent vasoconstrictor yet described. Considerable evidence has been amassed to suggest that these molecules play an important role in the regulation of basal renal hemodynamics and in the pathogenesis of acute renal failure. The purpose of this editorial review is to examine the data supporting a role for the endothelium in the regulation of renal hemodynamics in normal and pathological states.