A peptide vasoconstrictor; ligand for ETA and ETB (Kbs= 32.8 and 1.33 nM, respectively); induces β-arrestin recruitment in CHO-K1 cells expressing human ETA and ETB (pD2s =8.75 and 8.55, respectively); induces vasoconstriction in isolated rat mesenteric arterial beds (ED50 = 90.8 pmol); induces contraction of isolated rat uteri; restores vasoconstriction of vessels at the follicular apex of the ovarian follicle and ovulation in Amhr2cre/+ mice