Summary: Endothelin-1, a 21-amino acid peptide from vascular endothelial cells of different mammalian species, is one of the most potent vasoconstrictors. ET-1 exerts a wide variety of effects on both vascular and non-vascular (e.g. heart, lung, brain) tissues. Also ET-1 plays a central role in lung fibrosis.http://www.creative-peptides.com/product/endothelin-human-bovine-dog-mouse-porcine-rat-acetate-item-10-101-82-46.html