Endothelin

Endothelin

Endothelins are a family of vasoactive peptides se-creted by endothelial cells. The three major endothelin peptides are all composed of 21 amino acids. Endo-thelins are the most potent vasoconstrictors known. Contraction of vascular smooth muscle in response to endothelin is associated with an increase in intracellular calcium. Increases in endothelin levels have been re-ported in patients with vasospastic, hypoxic, and isch-emic diseases. The two identified isoforms of endothelin receptors have differing affinity for the three endothe-lin peptides. Selective and nonselective endothelin re-ceptor antagonists are in development for potential use in the treatment of hypertension and other disorders as-sociated with increased vascular resistance