Endothelins and Related Peptides
Endothelins are a family of peptides, which include endothelin-1 (ET-1), endothelin-2 (ET-2) and endothelin-3 (ET-3), each containing 21 amino-acids. ET-1 is a peptide secreted mainly by vascular endothelial cells, the predominant isoform expressed in vasculature and the most potent vasoconstrictor currently known. Endothelin peptides constrict blood vessels and consequently raise blood pressure. Typically the amounts of endothelins are kept in balance by homeostatic mechanisms, but complications arise when they are over-expressed and contribute to high blood pressure or hypertension and heart disease. Therefore, antagonists to endothelin receptors may play important roles in the treatment of cardiovascular diseases associated with regional or systemic vasoconstriction.