An isolated peptide having the following structural formula IA or IB A1-A2-A3 -A4-A5-A6-A7-A8-A9-A10 IA A10-A9-A8-A7-A6-AS-A4-A3-A2-A1 IB wherein A1 is Asp, D-Asp, Glu, D-Glu, pyroglutamate, D-pyroglutamate, Gln, D-Gln, Asn, D-Asn, bhAsp, Ida, Ida(NHPal), or N-MeAsp; A2 is Thr, D-Thr, Ser, D-Ser, Val, D-Val, Ile, D-Ile, Ala, D-Ala Tle, Inp, Chg, bhThr, or N-MeThr; A3 is His, D-His, Asn, D-Asn, Arg, D-Arg, L-His(π-Me), D-His(π-Me), L-His(τ-Me), or D-His(τ-Me); A4 is Phe, D-Phe, Leu, D-Leu, Ile, D-Ile, Trp, D-Trp, Tyr, D-Tyr, Phg, bhPhe, Dpa, Bip, 1Nal, 2Nal, bhDpa, Amc, PheF5, hPhe, Igl, or cyclohexylalanine; A5 is Pro, D-Pro, Ser, D-Ser, Oic, bhPro, trans-4-PhPro, cis-4-PhPro, cis-5-PhPro, or Idc; A6 is Arg; A7 is Cys, D-Cys, Ser, D-Ser, Ala, D-Ala, Cys(S-tBut), homoCys, Pen, Pen, preferably S-tertiary butyl-cysteine, Cys(S-S-Pal), Cys(S-S-cysteamine-Pal), Cys(S-S-Cys-NHPal), or Cys(S-S-Cys); A8 is Arg, D-Arg, D-Ile, Leu, D-Leu, Thr, D-Thr, Lys, D-Lys, Val, D-Val, D-Nω,ω-dimethyl-arginine, L-Nω,ω-dimethyl-arginine, D-homoarginine, L-homoarginine, D-norarginine, L-norarginine, citrulline, a modified Arg wherein the guanidinium group is modified or substituted, Norleucine, norvaline, bhIle, Ach, N-MeArg, or N-Melle; A9 is Phe, D-Phe, Leu, D-Leu, Ile, D-Ile, Tyr, D-Tyr, Trp, D-Trp, Phe-R a, D-Phe-R a, Dpa-R a, D-Dpa-R a, Trp-R a, bhPhe-R a, PheF5, N-MePhe, benzylamide, 2-aminoindane, bhPhe, Dpa, Bip, INal, 2Nal, bhDpa, and cyclohexylalanine, which may or may not have R a linked thereto, preferably bhPhe and bhPhe-R a, wherein R a is: palmitoyl-PEG-, wherein PEG is PEG11 or miniPEG3, palmitoyl-PEG-PEG, wherein PEG is PEG11 or miniPEG3, butanoyl -PEG11-, octanoyl (C8, Caprylic)-PEG11-, palmitoyl -PEG11-, or tetracosanoyl (C24, Lignoceric)-PEGll-; and A10 is Cys, D-Cys, Ser, D-Ser, Ala, D-Ala, Ida, Ahx-Ida(NHPal), or Ahx-Ida(NBzl2); wherein the carboxy-terminal amino acid is in amide or carboxy- form; wherein at least one sulfhydryl amino acid is present as one of the amino acids in the sequence; and wherein A1, A1 to A2, A10, or a combination thereof are optionally absent, with the proviso that the peptide is not one of the peptides as set forth in Table 1. A1 is Asp, D-Asp, Glu, D-Glu, pyroglutamate, D-pyroglutamate, Gln, D-Gln, Asn, D-Asn, bhAsp, Ida, Ida(NHPal), or N-MeAsp; A2 is Thr, D-Thr, Ser, D-Ser, Val, D-Val, Ile, D-Ile, Ala, D-Ala Tle, Inp, Chg, bhThr, or N-MeThr; A3 is His, D-His, Asn, D-Asn, Arg, D-Arg, L-His(π-Me), D-His(π-Me), L-His(τ-Me), or D-His(τ-Me); A4 is Phe, D-Phe, Leu, D-Leu, Ile, D-Ile, Trp, D-Trp, Tyr, D-Tyr, Phg, bhPhe, Dpa, Bip, 1Nal, 2Nal, bhDpa, Amc, PheF5, hPhe, Igl, or cyclohexylalanine; A5 is Pro, D-Pro, Ser, D-Ser, Oic, bhPro, trans-4-PhPro, cis-4-PhPro, cis-5-PhPro, or Idc; A6 is Arg; A7 is Cys, D-Cys, Ser, D-Ser, Ala, D-Ala, Cys(S-tBut), homoCys, Pen, Pen, preferably S-tertiary butyl-cysteine, Cys(S-S-Pal), Cys(S-S-cysteamine-Pal), Cys(S-S-Cys-NHPal), or Cys(S-S-Cys); A8 is Arg, D-Arg, D-Ile, Leu, D-Leu, Thr, D-Thr, Lys, D-Lys, Val, D-Val, D-Nω,ω-dimethyl-arginine, L-Nω,ω-dimethyl-arginine, D-homoarginine, L-homoarginine, D-norarginine, L-norarginine, citrulline, a modified Arg wherein the guanidinium group is modified or substituted, Norleucine, norvaline, bhIle, Ach, N-MeArg, or N-Melle; A9 is Phe, D-Phe, Leu, D-Leu, Ile, D-Ile, Tyr, D-Tyr, Trp, D-Trp, Phe-R a, D-Phe-R a, Dpa-R a, D-Dpa-R a, Trp-R a, bhPhe-R a, PheF5, N-MePhe, benzylamide, 2-aminoindane, bhPhe, Dpa, Bip, INal, 2Nal, bhDpa, and cyclohexylalanine, which may or may not have R a linked thereto, preferably bhPhe and bhPhe-R a, wherein R a is: palmitoyl-PEG-, wherein PEG is PEG11 or miniPEG3, palmitoyl-PEG-PEG, wherein PEG is PEG11 or miniPEG3, butanoyl -PEG11-, octanoyl (C8, Caprylic)-PEG11-, palmitoyl -PEG11-, or tetracosanoyl (C24, Lignoceric)-PEGll-; and palmitoyl-PEG-, wherein PEG is PEG11 or miniPEG3, palmitoyl-PEG-PEG, wherein PEG is PEG11 or miniPEG3, butanoyl -PEG11-, octanoyl (C8, Caprylic)-PEG11-, palmitoyl -PEG11-, or tetracosanoyl (C24, Lignoceric)-PEGll-; and A10 is Cys, D-Cys, Ser, D-Ser, Ala, D-Ala, Ida, Ahx-Ida(NHPal), or Ahx-Ida(NBzl2); wherein the carboxy-terminal amino acid is in amide or carboxy- form; wherein at least one sulfhydryl amino acid is present as one of the amino acids in the sequence; and wherein A1, A1 to A2, A10, or a combination thereof are optionally absent, with the proviso that the peptide is not one of the peptides as set forth in Table 1.