Urotensin II and the Circulatory System

Urotensin II (UII), first isolated from the spinal cord of teleost fish, is the most potent vasoconstrictor known. It is more potent than endothelin-1 and acts through UT-II, a seven-transmembrane-domain, G-protein-coupled receptor. Human UII is an 11-amino-acid cyclic peptide that is expressed in various tissues, including the central nervous system, heart, kidney, and blood vessels. It circulates in human plasma, and its plasma level is elevated in renal failure, congestive heart failure, diabetes, and portal hypertension. In the kidney, UII has vasodilatory and natriuretic effects, mediated through nitric oxide. The development of UII-receptor antagonists may provide a useful research tool, and a novel treatment for cardiorenal diseases.