A compound having the formula R1-Z-R2 in which R1 is H, C1-4 alkyl, acetyl, formyl, benzoyl or trifluoroacetyl； R2 is OH or NH2； and Z is a peptide having the formula I: His-X2-Gln-Gly-Thr-Phe-Thr-Ser-Asp-Tyr-Ser-X12-Tyr-Leu-Asp-X16-X17-Ala-Ala-X20 - X21-Phe-Val-X24-Trp-Leu-X27-X28-Ala-X30； (I) in which X2 is selected from Aib or Ser； X12 is selected from Lys, Arg and Leu； X16 is selected from Arg and X； X17 is selected from Arg and X； X20 is selected from Arg, His and X； X21 is selected from Asp and Glu； X24 is selected from Ala and X； X27 is selected from Leu and X； X28 is selected from Arg and X； X30 is X or is absent； wherein at least one of X16, X17, X20, X24, X27, X28 and X30 is X； and wherein each residue X is independently selected from the group consisting of Glu, Lys, Ser, Cys, Dbu, Dpr and Orn； wherein the side chain of at least one residue X is conjugated to a lipophilic substituent having the formula: (i) Z1, wherein Z1 is a lipophilic residue conjugated directly to the side chain of X； or (ii) Z1Z2, where Z1 is a lipophilic residue, Z2 is a spacer and Z1 is conjugated to the side chain of X by Z2； with the proviso that Z is not HSQGTFTSDYSKYLDS-K (Hexadecanoil-g-Glu) -AAHDFVEWLLRA.Un compuesto que tiene la fórmula R1-Z-R2 en la que R1 es H, alquilo C1-4, acetilo, formilo, benzoílo o trifluoroacetilo； R2 es OH o NH2； y Z es un péptido que tiene la fórmula I: His-X2-Gln-Gly-Thr-Phe-Thr-Ser-Asp-Tyr-Ser-X12-Tyr-Leu-Asp-X16-X17-Ala-Ala-X20- X21-Phe-Val-X24-Trp-Leu-X27-X28-Ala-X30； (I) en la que X2 se selecciona de Aib o Ser； X12 se selecciona de Lys, Arg y Leu； X16 se selecciona de Arg y X； X17 se selecciona de Arg y X； X20 se selecciona de Arg, His y X； X21 se selecciona de Asp y Glu； X24 se selecciona de Ala y X； X27 se selecciona de Leu y X； X28 se selecciona de Arg y X； X30 es X o está ausente； en la que al menos uno de X16, X17, X20, X24, X27, X28 y X30 es X； y en donde cada resto X se selecciona independientemente del grupo que consiste en Glu, Lys, S
