<p>A peptide represented by general formula (I) or a pharmacologically acceptable salt thereof, wherein Q represents a physiologically active peptide residue; Xs represent the same or different alpha -amino acid residues; M represents Gly or Cys; and m and n represent integers of, respectively, 5 to 8 and 0 to 3. The peptide ismore stable and/or active than straight-chain physiologically active peptides having no cyclic peptide linkage. <IMAGE></p>
