amylin; islet amyloid polypeptide; diabetes-associated peptide; DAP; insulinoma amyloid peptide (IAPP)

Function

• synergistic with insulin in lowering plasma glucose
• reduces food intake, delays gastric emptying, inhibits secretion of digestive juices (gastric acid, pancreatic enzymes, bile)
• inhibits secretion of glucagon
• some effects occur via recognition of amylin by receptors in the area postrema of the brain stem
• effects of amylin may be over-ridden during times of hypoglycemia
• selectively inhibits insulin-stimulated glucose utilization & glycogen deposition in muscle
• does not affect adipocyte glucose metabolism
• also acts in bone metabolism along with calcitonin & CGRP
  • can elicit hypocalcemic effects of calcitonin
  • can elicit vasodilator effects of CGRP
• amylin is degraded, in part, by insulin-degrading enzyme

Structure

• 37 residue polypeptide
• amylin is 46% homologous to beta-CGRP

Compartment

secreted

Expression

• secreted by pancreatic beta-cells at the same time as insulin; stoichiometry roughly 1 amylin to 100 insulin

Pathology

• IAPP is the peptide subunit of amyloid found in pancreatic islets of type 2 diabetic patients & in patients with insulinomas
• an increased secretion of amylin by beta cells may predispose to amyloid deposition & inhibit action of insulin in peripheral tissues
• amylin-containing amyloid may result in cell-death of islet beta-cells

Pharmacology

• pramlintide (Symlin) is a synthetic amylin indicated for reducing insulin requirements in type 1 & type 2 diabetics

More general terms

• secreted peptide
• amyloid

More specific terms

• pramlintide (Symlin)

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=3375
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:3375
• OMIM: https://mirror.omim.org/entry/147940
• UniProt: http://www.uniprot.org/uniprot/P10997.html