Exendins are secreted by lizard venom gland. They have a VIP/secretin-like biological activity when binding to the exendin receptor. Exedin-4 (named Byetta, Amylin/Eli Lilly) is used for the treatment of type 2 diabetes by enhancing insulin secretion.H-His-Gly-Glu-Gly-Thr-Phe-Thr-Ser-Asp-Leu-Ser-Lys-Gln-Met-Glu-Glu-Glu-Ala-Val-Arg-Leu-Phe-Ile-Glu-Trp-Leu-Lys-Asn-Gly-Gly-Pro-Ser-Ser-Gly-Ala-Pro-Pro-Pro-Ser-NH2 or H-HGEGTFTSDLSKQMEEEAVRLFIEWLKNGGPSSGAPPPS-NH2