Adrenomedullin (AM), alpha- and beta-calcitonin gene-related peptide(CGRP), calcitonin (CT), and amylin are homologous polypeptides with overlapping biological actions such as vasodilatation and inhibition of bone resorption. Amylin (Islet/insulinoma amyloid polypeptide or IAPP) is a 37-amino acid monomeric polypeptide isolated from pancreatic amyloid. This protein, with a calculated molecular mass of 4 kDa, is a major component of amyloid-rich pancreatic extracts of three type 2 diabetic patients. IAPP has cysteine residues in positions 2 and 7, a feature found in all known calcitonin gene-related peptides. IAPP shows 46% amino acid sequence homology with CGRP II. Since IAPP has been demonstrated immunochemically in normal beta cells of several mammals, it probably has an important role in respect to pancreatic islet function.