Abstract: The invention relates to a peptide of formula W-DPhe-Arg-Z (I) and to a conjugate thereof of a formula A-W-DPhe-Arg-Z (II), wherein A is a radical corresponding to a monocarboxylic acid of general formula HOOC—R (III), wherein R is an linear or branched possibly substituted by a hydroxy group aliphatic C1-C24 radical which can comprise one or several unsaturations, preferably from 1 to 6 unsaturations, a lipoic acid or the reduced form thereof, a dihydrolipoic acid, N-lipoyl-lysine or a phenylbutyric acid, W is His, Ala-His, Ala-Ala-His, Nle-Ala-His, DTrp-Ala-His, Nle-Trp-His, Lys, Ala-Lys, Nle-Ala-Lys, Orn, Ala-Orn, Nle-Ala-Orn, Ala, Nle-Ala-Ala, Arg, Ala-Arg.