Islet Amyloid, Islet-Amyloid Polypeptide, and Diabetes Mellitus

Abstract

A PREVIOUSLY undescribed protein, called insulinoma- or islet-amyloid polypeptide (IAPP), was recently identified as the principal constituent of amyloid deposits in a human insulin-producing tumor (insulinoma).¹ This same protein was subsequently found to be the principal constituent of amyloid isolated from the pancreatic tissue of patients with Type II (non-insulin-dependent) diabetes mellitus and of adult cats with diabetes.^{2 , 3} Although these IAPP-derived amyloid deposits (Fig. 1) are the most characteristic morphologic abnormality of islets from patients with Type II diabetes mellitus^{4 5 6 7} and adult diabetic cats,^{8 , 9} the relation of islet amyloid to diabetes mellitus has often been discounted and remains controversial. This . . .