Effect of 4,7,10,13,16,19-docosahexaenoic acid on triglyceride accumulation and secretion in rat hepatocytes in culture.

We have investigated the effect of oleic (18:1) and 4,7,10,13,16,19-docosahexaenoic (22:6 omega 3) acids on triglyceride (TG) accumulation, secretion and reuptake in rat hepatocytes in culture. We also calculated the percentage of total TG, TG-esterified 18:1 and TG-esterified 22:6 omega 3 that were secreted relative to the total accumulation (intra + extracellular TG). Both fatty acids were incorporated mainly in the intracellular TG fraction. Treatment with 18:1 but not with 22:6 omega 3 increased the quantity of TG secreted into the culture medium relative to controls. Treatment with 22:6 omega 3 caused a greater accumulation of intracellular TG than 18:1. This arises in part from the preferential retention of 22:6 omega 3-enriched TG by the hepatocytes. At 24 hr, there was no longer any difference in the net secretion of TG by 18:1 and 22:6 omega 3-treated cells, which may be a consequence of the reuptake of TG-esterified 18:1. There was no reuptake of TG-esterified 22:6 omega 3. We conclude that inhibition of hepatocyte TG synthesis is not obligatory for 22:6 omega 3-induced diminution of TG secretion.