Per Westermark1, Christer Wernstedt1, Erik Wilander1, D. W. Hayden2,3,4, Timothy D. O’Brien2,3,4, K. H. Johnson2,3,4
1 Uppsala University
2Department of Pathology University Hospital S-751 85 Uppsala, Sweden
3University of Minnesota, St. Paul, MN 55108
4tLudwig Institute for Cancer Research, Uppsala Branch, Box 595, S-751 23 Uppsala, Sweden; and tDepartment of Veterinary Pathobiology, College of Veterinary Medicine,
Tóm tắt
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 greater than 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.
