D-Phe-L-Cys(1)-L-Tyr-D-Trp-L-Lys-L-Val-L-Cys(1)-L-Trp-NH2

D-Phe-Cys-Trp-D-Trp-Lys-Val-Cys-Trp-CONH2(disulfide Cys2-Cys7)

D-Phe-Cys-Tyr-D-Trp-Lys-Val-Cys-Trp-NH2 (Disulfide bridge Cys2-Cys7)