EICOSAPENTAENOIC ACID (C20-5) AUGMENTS GLUCOSE-INDUCED INSULIN-SECRETION FROM BETA-TC3 INSULINOMA CELLS

There has been a large amount of recent literature suggesting that ome ga-3 unsaturated fatty acids found in fish oils should be incorporated into the diet for the purpose of decreasing serum cholesterol levels. Inclusion of these fatty acids in the diet has been shown to decrease total serum cholesterol as well as low-density lipoprotein cholestero l. Some of these trials have been complicated by the fact that many of the subjects are afflicted with non-insulin-dependent diabetes mellit us. Unfortunately, the effects of omega-3 unsaturated fatty acids on i nsulin secretion have not been well characterized. In this study, we h ave examined the effect of a common omega-3 unsaturated fatty acid, ei cosapentaenoic acid (C20:5), on insulin secretion. Using the beta-TC3 insulinoma cell line as a model system for studying insulin exocytosis , C20:5 selectively potentiated glucose-induced insulin secretion. At the same concentration at which it significantly increased glucose-ind uced insulin secretion, C20:5 did not affect glucose metabolism or int racellular free calcium concentrations. C20:5 also augmented potassium -induced insulin secretion. These data suggest that C20:5, an abundant omega-3 unsaturated fatty acid, acts to augment insulin secretion in a glucose-dependent manner.