Amyloid deposits localized to the islets of Langerhans are typical of non-insulin-dependent human diabetes mellitus and of diabetes mellitus in adult cats. Amyloid deposits also commonly occur in insulin-producing pancreatic tumors. We have purified a major protein - insulinoma or islet amyloid polypeptide (IAPP) - from human and cat islet amyloid and from amyloid of a human insulinoma IAPP from human insulinoma contained 37 amino acid residues and had a theoretical molecular mass of 3850 Da. The amino acid sequence is unique but has >40% identity with the human calcitonin gene-related peptide. A partial amino acid sequence of cat islet IAPP corresponding to positions 1-27 of human insulinoma IAPP was identical to the human IAPP except for substitutions in three positions. An antiserum raised to a synthetic human insulinoma IAPP-(7-17) undecapeptide showed specific immunohistochemical reactivity with human and cat islet amyloid and with islet B cells. The significance of this pancreatic neuropeptide-like protein is unknown, but it is suggested that it may exert an important endocrine regulatory effect.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - 1987|