A peptide vasoconstrictor and agonist of ETA and ETB (IC50s = 0.15 and 0.12 nM, respectively); induces contraction of pig coronary artery strips (EC50 = 0.52 nM), vasoconstriction of pig cardiac ventricular membrane (120% of control), and increases mean early pressor phase blood pressure by 66 mg Hg in rats when administered at a dose of 1 nmol/kg; stabilizes and induces nuclear translocation of HIF-1α and HIF-2α) via ETB in human lymphatic endothelial cells