CALCITONIN, CALCITONIN-GENE-RELATED PEPTIDE, ADRENOMEDULLIN AND AMYLIN - HOMOLOGOUS PEPTIDES, SEPARATE RECEPTORS AND OVERLAPPING BIOLOGICALACTIONS

Calcitonin, calcitonin gene-related peptide, adrenomedullin and amylin are structurally related peptides with N-terminal 6-7 amino acid ring structures linked by a disulfide bridge and with amidated C-termini. Among the related bioactive peptides, the structures of the calcitonin receptor and subtypes thereof have been identified so far through mol ecular cloning. Cross-reaction between receptors of calcitonin, calcit onin gene-related peptide, adrenomedullin and amylin, as well as overl apping biological actions, anticipate that the respective receptors be long to a family of G-protein-coupled receptors that include those of parathyroid hormone, secretin and vasointestinal peptide.