Endothelin

Endothelin is a potent, long-acting vasoconstrictor and bronchoconstrictor. It is secreted initially as a prohormone by the vascular endothelium and later converted to ET-1 by the action of endothelin converting enzyme. It acts via interaction with a G-protein linked to phospholipase C leading to calcium release. Endothelin is thought to be important in the pathogenesis of many diseases including primary pulmonary hypertension (endothelin antagonists are now used), cardiac failure, hepatorenal syndrome and Raynaud's

Promotes release

• angiotensin II
• ADH
• hypoxia
• mechanical shearing forces

Inhibits release

• nitric oxide
• prostacyclin

Raised levels in

• MI
• heart failure
• ARF
• asthma
• primary pulmonary hypertension