A peptide represented by formula: wherein P 1 represents -R A1, or -CO-R A1, wherein R A1 represents a hydrogen atom, or a C 1-6 alkyl group; P 2 represents -NH 2 or -OH; A2 represents Aib or D-Ala; A6 represents Iva, Phe, or Val; A7 represents Ile, Lys, or Val; A8 represents Ser; A9 represents Asp, Leu, or Phe; A10 represents Tyr; A11 represents Aib or Ser; A12 represents Ile; A13 represents Aib, Ala, Gln, Leu, Tyr, or D-Iva; A14 represents Leu; A15 represents Asp, Glu, Lys, Ser, or Tyr; A16 represents Arg or Lys; A17 represents Aib, Gln, or Ile; A18 represents Ala or His; A19 represents Gln or Ser; A20 represents Aib, Ala, or Gln; A21 represents Asn, Asp, Glu, Leu, or Ser; A22 represents Phe or aMePhe; A23 represents Ile or Val; A24 represents Arg, Asn, Asp, Lys, or Lys(Ac); A25 represents Trp; A26 represents Aib, Iva, or Leu; A27 represents Leu; A28 represents Ala, Arg, Lys, or Lys(Ac); A29 represents Gln or Gly; A30 represents Arg, Gly, or a deletion; A31 represents Pro or a deletion; A32 represents Ser or a deletion; A33 represents Ser or a deletion; A34 represents Gly or a deletion; A35 represents Ala or a deletion; A36 represents Pro or a deletion; A37 represents Pro or a deletion; A38 represents Pro or a deletion; A39 represents Lys, Ser, or a deletion; A40 represents Arg, Lys, or a deletion; and one or two amino acids selected from A12, A14 and A17 optionally represent Lys, and R represents X-L-, wherein X-L- represents Trda-GGGG-(Trda:C13 diacid), Trda-GGGGG-, Trda-GGGGGG-, Teda-GGGG-(Teda:C14 diacid), Teda-GGGGG-, Teda-GGGGGG-, Peda-GGGG-(Peda:C15 diadic), Peda-GGGGG-, Peda-GGGGGG-, Heda-GGGG-(Heda:C16 diacid), Heda-GGGGG-, Heda-GGGGGG-, Hepda-GGGG-(Hepda:C17 diacid), Hepda-GGGGG-, Hepda-GGGGGG-, Oda-GGGG-(Oda:C18 diacid), Oda-GGGGG-, Oda-GGGGGG-, Eda-GGGG-(Eda:C20 diacid), Eda-GGGGG-, Eda-GGGGGG-, Eda-GGGGGGGGG-; provided that where all A31 to A40 represent deletions, then A2 represents Aib, or a salt thereof. P 1 represents -R A1, or -CO-R A1, wherein R A1 represents a hydrogen atom, or a C 1-6 alkyl group; P 2 represents -NH 2 or -OH; A2 represents Aib or D-Ala; A6 represents Iva, Phe, or Val; A7 represents Ile, Lys, or Val; A8 represents Ser; A9 represents Asp, Leu, or Phe; A10 represents Tyr; A11 represents Aib or Ser; A12 represents Ile; A13 represents Aib, Ala, Gln, Leu, Tyr, or D-Iva; A14 represents Leu; A15 represents Asp, Glu, Lys, Ser, or Tyr; A16 represents Arg or Lys; A17 represents Aib, Gln, or Ile; A18 represents Ala or His; A19 represents Gln or Ser; A20 represents Aib, Ala, or Gln; A21 represents Asn, Asp, Glu, Leu, or Ser; A22 represents Phe or aMePhe; A23 represents Ile or Val; A24 represents Arg, Asn, Asp, Lys, or Lys(Ac); A25 represents Trp; A26 represents Aib, Iva, or Leu; A27 represents Leu; A28 represents Ala, Arg, Lys, or Lys(Ac); A29 represents Gln or Gly; A30 represents Arg, Gly, or a deletion; A31 represents Pro or a deletion; A32 represents Ser or a deletion; A33 represents Ser or a deletion; A34 represents Gly or a deletion; A35 represents Ala or a deletion; A36 represents Pro or a deletion; A37 represents Pro or a deletion; A38 represents Pro or a deletion; A39 represents Lys, Ser, or a deletion; A40 represents Arg, Lys, or a deletion; and one or two amino acids selected from A12, A14 and A17 optionally represent Lys, and R represents X-L-, wherein X-L- represents Trda-GGGG-(Trda:C13 diacid), Trda-GGGGG-, Trda-GGGGGG-, Teda-GGGG-(Teda:C14 diacid), Teda-GGGGG-, Teda-GGGGGG-, Peda-GGGG-(Peda:C15 diadic), Peda-GGGGG-, Peda-GGGGGG-, Heda-GGGG-(Heda:C16 diacid), Heda-GGGGG-, Heda-GGGGGG-, Hepda-GGGG-(Hepda:C17 diacid), Hepda-GGGGG-, Hepda-GGGGGG-, Oda-GGGG-(Oda:C18 diacid), Oda-GGGGG-, Oda-GGGGGG-, Eda-GGGG-(Eda:C20 diacid), Eda-GGGGG-, Eda-GGGGGG-, Eda-GGGGGGGGG-; provided that where all A31 to A40 represent deletions, then A2 represents Aib, or a salt thereof.