amylin

Amylin, also known as islet amyloid polypeptide (IAPP), is a 37-amino-acid peptide hormone co-secreted with insulin by pancreatic beta cells in response to nutrient intake. It helps regulate postprandial glucose by slowing gastric emptying, suppressing glucagon secretion, and promoting satiety. Amylin's effects are mediated through amylin receptors, which are complexes formed by the calcitonin receptor (CTR) and receptor activity-modifying proteins (RAMPs) found in the brain and peripheral tissues.

Amylin is encoded by the IAPP gene on chromosome 12 and is produced from the same prohormone as calcitonin gene-related peptide. It is stored in secretory vesicles alongside insulin and released in response to meals. Normal amylin action complements insulin in regulating glucose homeostasis, particularly after food intake.

In type 1 diabetes, loss of beta cells leads to little or no amylin production. In type 2 diabetes, amylin secretion may be initially increased, but chronic beta-cell dysfunction and islet amyloid formation can reduce functional beta-cell mass and exacerbate disease progression. Islet amyloid, composed of aggregated IAPP, is observed in many individuals with type 2 diabetes and is associated with beta-cell failure.

Therapeutically, pramlintide is a synthetic analog of amylin approved as an adjunct to mealtime insulin for adults with type 1 or type 2 diabetes. It slows gastric emptying, suppresses postprandial glucagon, and promotes satiety to improve glycemic control and can aid weight loss. It is not insulin and must be used with mealtime insulin, with careful dose titration to minimize hypoglycemia risk. Common adverse effects include nausea and vomiting; hypoglycemia risk increases if meals are skipped or insulin doses are not adjusted.