Endothelin 2 (ET-2) is a protein encoded by the EDN2 gene in humans. It was first discovered in 1988 by Yanagisawa and team[5] and belongs to a family of three endothelinpeptideisoforms (ET-1, ET-2, ET-3), which constrict blood vessels. ET-2 is encoded by genes on separate chromosomes to its isoforms and is mainly produced in vascular endothelial cells of the kidney, placenta, uterus, heart, central nervous system and intestine.[6] It becomes present in the blood of animals and humans at levels ranging from 0.3pg/ml to 3pg/ml.[7] ET-2 acts by binding to two different G-protein coupled receptors (GPCRs), the endothelin A receptor (EDNRA) and the endothelin B receptor (EDNRB).[8]