Eicosapentaenoic Acid C205 Augments GlucoseInduced Insulin Secretion from βTC3 Insulinoma Cells

There has been a large amount of recent literature suggesting that ω-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 cholesterol. Some of these trials have been complicated by the fact that many of the subjects are afflicted with non-insulin-dependent diabetes mellitus. Unfortunately, the effects of ω-3 unsaturated fatty acids on insulin secretion have not been well characterized. In this study, we have examined the effect of a common ω-3 unsaturated fatty acid, eicosapentaenoic acid (C20: 5), on insulin secretion. Using the β-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-induced insulin secretion, C20:5 did not affect glucose metabolism or intracellular free calcium concentrations. C20:5 also augmented potassium-induced insulin secretion. These data suggest that C20:5, an abundant ω-3 unsaturated fatty acid, acts to augment insulin secretion in a glucose-dependent manner.