Amylin, or Islet Amyloid Polypeptide (IAPP), is a 37-residue peptide hormone secreted by pancreatic β-cells at the same time as insulin (in a roughly 100:1 ratio). Amylin functions as part of the endocrine pancreas and contributes to glycemic control. Although amylin's complete function may not yet be known, it has been shown to slow gastric emptying, promote satiety, inhibit secretion of glucagon during hyperglycemia, and therein reduce the total insulin demand. As insulin lowers blood glucose and glucagon raises blood glucose, amylin supports the stability of blood glucose levels in effect by slowing the rate that digested glucose enters the bloodstream.
Rodent amylin knockouts are known to fail to achieve the normal anorexia following food consumption. Because it is an amidated peptide, like many neuropeptides, it is believed to be responsible for the anorectic effect.
There appears to be at least three distinct receptor complexes that bind with high affinity to amylin. All three complexes contain the calcitonin receptor at the core, plus one of three Receptor activity-modifying proteins, RAMP1, RAMP2, or RAMP3.