Amylin regulation of fuel metabolism.

The 37-amino acid amylin, co-secreted from the pancreatic beta cells with insulin in response to nutrient stimuli has actions in a number of tissues of metabolic interest. In muscle it opposes glycogen synthesis and activates glycogenolysis, an action likely to underly its stimulation of lactate flux. Amylin therefore appears to have the effect of transposing carbon from peripheral stores to the liver, where it is made available for hepatic synthesis of glucose, glycogen, and lipid. While amylin induces insulin resistance in skeletal muscle, it does not oppose insulin action in fat and may therefore favor fuel deposition in this tissue. Amylin acts on the beta cell to inhibit insulin secretion. Relative impairment of insulin secretion, muscle insulin resistance, relatively preserved insulin sensitivity in fat, increased lactate turnover, and increased hepatic glucose production are features of insulin resistance and early non-insulin-dependent diabetes mellitus. Amylin is elevated in these dysfunctional metabolic states and may be involved in their pathogenesis.