EFFECT OF CHRONIC INCUBATION OF CACO-2 CELLS WITH EICOSAPENTAENOIC ACID (20 5, N-3) AND OLEIC-ACID (18/1, N-9) ON TRIACYLGLYCEROL PRODUCTION/

CaCo-2 monolayers, cultured for 1 week after reaching confluence, were incubated with micellar solutions of fatty acids for up to 7 days. Th ese conditioned cells were incubated acutely (5 h) with eicosapentaeno ic acid and oleic acid, and the levels of cell-associated and secreted triacylglycerol were determined. With acute addition of oleic acid, b oth cell-associated and secreted triacylglycerol were decreased in cel ls chronically exposed to eicosapentaenoic acid. This effect was obser ved after as little as 2 days of chronic incubation with eicosapentaen oic acid. A further decrease was found when these cells were incubated acutely with eicosapentaenoic acid, regardless of which radioisotopes were used to label precursors in the incubation media. The secretion of both labelled and total triacylglycerol and apolipoprotein B was re duced approximately 50% in cells incubated chronically with eicosapent aenoic acid. The amounts of triacylglycerol and apolipoprotein B withi n the cells were not decreased by chronic exposure to eicosapentaenoic acid. Our data indicate that CaCo-2 cells chronically incubated with eicosapentaenoic acid secrete significantly less triacylglycerol than cells incubated chronically with oleic acid. When eicosapentaenoic aci d was also included acutely, triacylglycerol secretion was reduced eve n more. We conclude that chronic exposure of eicosapentaenoic acid to this intestinal cell type reduces the rate of chylomicron secretion an d may help explain the decreased postprandial lipaemia observed in hum ans taking fish oil supplements.