IAPP as a regulator of glucose homeostasis and pancreatic hormone secretion

IAPP is a 37-amino acid peptide that is predominantly expressed in pancreat ic 13 cells. Despite cosecretion from islets the relative amounts of IAPP a nd insulin may vary. Since IAPP was first described as the major peptide co nstituent of amyloid in the islets of Langerhans of subjects with type 2 di abetes and insulinoma, many studies have been devoted to investigating the role of IAPP in formation of amyloid deposits and in diabetes pathogenesis. However, there is growing evidence for IAPP as an active islet hormone in addition to insulin and glucagon in glucose metabolic control. An inhibitor y effect is seen by IAPP on gastric emptying, glycogen synthesis in skeleta l muscle, islet insulin and glucagon secretion, whereas a stimulatory effec t is seen on hepatic gluconeogenesis.