The endothelium-derived relaxing factor.

Over the past 25 years, it has become clear that the vascular endothelium plays an important role in the function of the cardiovascular system. Most recently, it has been established that endothelial cells can determine or modulate the response of vascular smooth muscle cells to vasoactive stimuli, by production of a labile factor (or factors) that has been named the "Endothelium-Derived Relaxing Factor" (EDRF). While much remains to be learned about the pathways responsible for the production and the effects of EDRF, and its role in cardiovascular physiology, it is apparent that the loss of this endothelium-derived vasodilator can have profound effects on vascular pharmacology and physiology that could be important to the pathologies associated with disease states.