Endothelin 1 (ET-1), also known as preproendothelin-1 (PPET1), is a protein that in humans is encoded by the EDN1gene. The protein encoded by this gene is proteolytically processed to release a secreted peptide termed endothelin 1. This peptide is a potent vasoconstrictor and is produced by vascular endothelial cells. Endothelin 1 is one of three isoforms of human endothelin.
Preproendothelin is precursor of the peptide ET-1. Endothelial cells convert preproendothelin to proendothelin and subsequently to mature endothelin, which the cells release.
Endothelin-1 receptor antagonists (Bosentan) are used in the treatment of pulmonary hypertension. Inhibition of these receptors prevents pulmonary vasculature constriction and thus decreases pulmonary vascular resistance.