Magnesium deprivation or short-term essential fatty acid deficiency in rats: effects on serum lipids, platelet fatty acid composition and arachidonic acid incorporation into platelet phospholipids.

The aim of this study was to evaluate the effect of short-term magnesium or essential fatty acid (EFA) deficiencies on plasma lipids, platelet fatty acid composition and [1-14C] arachidonic acid incorporation into platelet phospholipids. Weanling rats were fed purified diets (casein 20%, sucrose 70.5%, lipid 5%) for two weeks. The control and magnesium-deficient diets included corn oil as lipid source. The EFA-deficient diet included hydrogenated coconut oil. The fatty acid composition of serum lipids confirmed the linoleic acid deprivation in the EFA-deficient group. Significant changes in platelet fatty acid composition occurred in this limited period of time and arachidonic acid incorporation into platelet lipids was markedly increased. Magnesium deficiency induced hyperlipaemia. A significant decrease in the percentage of arachidonic acid in total serum lipids was observed, but fatty acid profile appeared quite different in the two deficiencies. In magnesium-deficient rats, the alteration in fatty acid composition of serum lipids was not associated with similar changes in fatty acid composition of platelet lipids. Arachidonic acid incorporation into platelet lipids was markedly increased in magnesium deficient animals as compared to control group. Relatively more arachidonic acid was incorporated into phosphatidylcholine and phosphatidylinositol when magnesium-deficient or EFA-deficient animals were compared to the control group.