Changes of linoleic, arachidonic and eicosapentaenoic acids in rat platelet, aorta and plasma lipids after changing from a sardine oil diet to a corn oil diet.

When rats were fed on a diet containing sardine oil (SO) for 10 days, 20:5 (eicosapentaenoic acid) was incorporated into the platelet, aorta and plasma lipids. The 20:5/20:4 (arachidonic acid) ratios of phospholipids were higher in platelets than in aortas. When the diet was changed from SO to corn oil (CO), the levels of 20: 5 in the plasma lipids and platelet phospholipids decreased with an increase of 20:4. Although the 20:5 levels of phospholipids in the aortas decreased, 20:4 did not increase during feeding with the CO diet for 4 days. The 20:5/20:4 ratios of the phosphatidylcholine in platelets and aortas rapidly changed from 5.0 and 1.1 to 2.4 and 0.6, respectively. The linoleic acid level of phosphatidylcholine in platelets and aortas increased rapidly by changing from the SO diet to the CO diet, but this fatty acid was not incorporated into phosphatidylinositol of the platelets and aortas.