Amylin.

Amylin is a 37 amino-acid peptide which is secreted from the pancreatic islets of Langerhans. It has major sequence homology with calcitonin gene related peptide. Amylin can precipitate out in these cells to form amyloid. Amylin is secreted by similar stimuli to those that secrete insulin. Amylin has a number of effects that may counteract the effect of secreted insulin, i.e., decreased second phase insulin secretion, increased hepatic glucose output, and inhibition of insulin effects on skeletal muscle. It must, however, be recognized that in many cases the doses necessary to produce these effects appear to be supraphysiological. The putative role of amylin in the hyperglycemia of aging and Type II diabetes mellitus therefore remains controversial. Amylin has a number of other effects including inhibition of osteoclastic activity, vasodilatation, anorectic effects and enhanced memory retention. This review postulates a role for amylin in the pathogenesis of a number of age-related changes.