EDN1 and endothelial dysfunction: Endothelial dysfunction (ED) results from an imbalance in the production of vasodilatory agents, such as nitric oxide (NO), endothelial-derived hyperpolarizing factors (EDHF), prostacyclin (PGI2), and vasoconstricting agents, including prostaglandin (PGH2), endothelin-1 (ET-1), and angiotensin-II (Ang-II).