| The endothelins are family of cysteine-rich peptides consisting of 21-amino acid and containing two intramolecular disulfide bridges that exert their vasoactive and mitogenic actions through G protein-coupled receptors. At the present, the existence of three active isoforms of ET (-1, -2, and -3), and two distinct receptors, ETA and ETB, is well documented (17). The active form of ET-1 arises from biologically inactive big-ET-1 through the action of a specific protease that removes 18 amino acids from its carboxyl terminal. This membrane-bound metallopeptidase, characterized by its sensitivity to phosphoramidon, is known as endothelin-converting enzyme-1 (ECE-1) . A growing body of evidence indicate that ET-1 is a major player in numerous disease states including congestive heart failure, pulmonary fibrosis, obesity and diabetes, as well as a key mediator of tissue repair and normal wound healing. |
