Effects of Dietary Vitamin E on Serum and Pulmonary Fatty Acids and Prostaglandins in Rats Fed Excess Linoleic Acid

Abstract

The interrelationships of dietary vitamin E and essential fatty acids and their effects on serum and pulmonary prostaglandin (PG) synthesis and fatty acid precursors were examined. In a preexperimental period, male weanling rats were depleted of essential fatty acids (EFA) by feeding on a hydrogenated coconut oil diet. At the end of 45 days, average serum triene:tetraene ratio for the EFA-deficient rats was 0.76. After a refeeding period with a 20% safflower oil diet and 0, 1 or 50 mg of dl-α-tocopheryl acetate daily, serum and pulmonary fatty acid profiles and PG synthesis were determined. A trend to growth depression on the high vitamin E diet was observed. Vitamin E supplementation seemed to have no significant effect on fatty acid composition or synthesis of PGE1, PGE2, PGF2α or PGI2 in lung. This may be due to the small lipid content and presumed inability of lung to accumulate excess vitamin E. Lung may, therefore, be resistant to such dietary manipulations. Serum PG synthesis was not affected by vitamin E dose, although the C20:4ω6/C18:2ω6 ratio in serum was significantly lowered on the high vitamin E diet.