The orphan receptor GPR14 has been found to be expressed predominantly in cardiovascular tissue and many serve as a receptor for urotensin II (human). Urotensin II (human) binds with high affinity to recombinant GPR14. It is found within both vascular and cardiac tissue. Urotensin II vasoconstrictive potency is reported to be an order of magnitude greater than that of endothelin-1 (ET-1), which would make it the most potent mammalian vasoconstrictor identified to date. Recently, our research data has shown that urotensin II is involved in the development of rat cardiac hypertrophy: Contractile response to human U II in rat and human pulmonary arteries was increased by endothelial factors, vascular tone, and the onset of pulmonary hypertension.