Direct effects of eicosapentaenoic and docosahexaenoic acids on phospholipid and triglyceride fatty acid pattern, glucose metabolism, ⁸⁶rubidium net uptake and insulin release in BRIN-BD11 cells

Abstract

The long-term metabolic and functional effects of a dietary deprivation of long-chain polyunsaturated ω3 fatty acids were recently investigated in second-generation ω3-depleted rats. This study represents the first attempt to explore the direct, but not immediate, effects of ω3 fatty acids on insulin-producing cells. For this purpose, BRIN-BD11 cells were cultured for 24 h in the absence or presence of both C20:5ω3 and C22:6ω3 (50 μM each) and, thereafter, examined for their phospholipid and triglyceride fatty acid pattern, and their metabolic, ionic, and secretory responses to d-glucose and/or non-nutrient insulinotropic agents. The prior culture in the presence of the two ω3 fatty acids provoked an enrichment of cell lipids in such ω3 fatty acids, changes in the phospholipid fatty acid pattern of long-chain polyunsaturated ω6 fatty acids as well as saturated and monodesaturated fatty acids, and cell steatosis. It minimized the relative increase in d-[5-³H]glucose utilization and d-[U-¹⁴C]glucose oxidation otherwise resulting from an increase in the concentration of the hexose from 1.1 to 11.1 mM. It also minimized the changes in ⁸⁶Rb⁺ net uptake otherwise provoked by rises in d-glucose concentration and decreased the absolute values for insulin output. It is concluded that the major changes in metabolic, cationic, and secretory behavior of the ω3-enriched BRIN-BD11 cells are paradoxically similar to those encountered in pancreatic islets from ω3-depleted rats and, in both cases, possibly attributable to a phenomenon of lipotoxicity.