In vitro effects of amylin on carbohydrate metabolism in liver cells

Amylin, a peptide found in pancreatic amyloid deposits, may be involved in NIDDM. The effects of biosynthetic human amylin on multiple aspects of carbohydrate metabolism were studied in freshly isolated and cultured liver cells (rat hepatocytes and HepG2 cells). Acute exposure of culture liver cells to amylin had no effect on glucose incorporation into glycogen. Amylin directly reduced glucose oxidation through the hexose monophosphate shunt. The glycolytic pathway was unaffected. Amylin stimulated both glycogenolysis and gluconeogenesis. These effects were largest at amylin concentrations of 1-10 pM. Insulin partially inhibited both of these responses. Glucagon stimulated glycogenolysis and gluconeogenesis to a similar extent as amylin but required concentrations 100- to 500-fold as high. Thus, amylin, at physiologic concentrations, can impair some aspects of glucose use in liver cells and is also capable of directly stimulating glucose production, suggesting a possible involvement of amylin in the impaired glucose disposal and elevated hepatic glucose output of NIDDM.