Hydrogenated fat high in trans monoenes with an adequate level of linoleicacid has no effect on prostaglandin synthesis in rats

Our study was designed to determine whether hydrogenated fat high in trans monoenes concentration affected prostaglandin synthesis. Corn oil (CO), but ter (B), hydrogenated vegetable oil (HF) and coating fat (CF) were used in this study. These fats were fed to rats for 10 wk at 10 g/100 g diet. The p hospholipid (PL) fatty acid content of platelets, aorta and heart was deter mined by gas liquid chromatography, and the in vitro aorta production of pr ostacyclin (PGI(2)) from exogenous or endogenous arachidonic acid (AA) was measured using the radioimmuno-assay (RIA) method. Serum thromboxane B-2 (T XB2) released by platelets as thromboxane A(2) (TXA(2)) during incubation o f whole blood was also measured by this method. In the group fed CF, AA was significantly lower in the PL of aorta, platelet and heart, and the ratio 20:3(n-9)/20:4(n-6) was greater than in the groups fed CO, B or HF, indicat ing that the group fed CF was essential fatty acid (EFA) deficient. Althoug h AA was significantly lower in the aorta and platelet PL of the group fed HF compared to the group fed CO, that difference did not affect the amounts of PGI(2) or TXB2 produced in these groups. The group fed CF had significa ntly less PGI(2) and TXB2 released by aorta and platelets than the other gr oups. This was the result of the reduced level of AA and the presence of hi gher amounts of 20:3(n-9) acid in the FL, which might act as a competitive inhibitor for cyclooxygenase. The aortic production of PGI(2) from exogenou s AA did not differ among the groups indicating that prostaglandin syntheta se was not affected by the dietary fat. We conclude that the consumption of hydrogenated fats high in trans 18:1 acids with adequate amount of linolei c acid had no effect on the amount of thromboxane or prostacyclin produced by platelet or aorta in vitro.