CHANGES IN PLATELET-AGGREGATION AND LIPID-METABOLISM IN RATS GIVEN DIETARY LIPIDS CONTAINING DIFFERENT N-3 POLYUNSATURATED FATTY-ACIDS

We compared the effects of different n-3 polyunsaturated fatty acids ( PUFA) on platelet aggregation and lipid metabolism in rats. alpha-lino lenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were used as n-3 PUFA sources. The rats were fed diets containi ng 10% lipids (polyunsaturated/saturated fatty acid (P/S) ratio = 1.0; n-3/n-6 =0.02 for the control group, 0.2 for the test groups) for two weeks. The platelet counts, platelet aggregation, and production of t hromboxane A(2) (TXA(2)), plasma total cholesterol (TC) and triacylgly cerols (TG) were not different between the ALA group and the control g roup, but showed a decreasing tendency for the EPA group and significa nt decreases for the DHA group. The production of prostacyclin in the aorta was significantly decreased in all of the n-3 PUFA groups when c ompared with that in the control group. Liver TC and TG concentrations were significantly decreased in the DHA group when compared with thos e in the control group. Based on the above, it is assumed that the phy siological action exerted by n-3 PUFA differs by type and that DHA is a more effective n-3 PUFA, both for suppressing platelet aggregation a nd for modulating lipid metabolism in the plasma and liver of rats.