Influence of diet on the acyl composition of phospholipids in endothelial cells and mitochondria of rat brain.

The effect of diet on phospholipid acyl groups of rat brain endothelial cells and mitochondria and of liver was determined. Rats were fed high-protein diets with a 4:1 linoleate/linolenate ratio but with 4.4%, 1.9%, or 0.8% of the caloric content provided by these essential fatty acids (cal % EFA) or were fed a fat-free diet. In capillary endothelial cells the greatest change occurred in the plasmalogen ethanolamine fraction, there being a significant reduction in the n-3 series of acyl groups and increase in the n-9 series as the cal % EFA was reduced. Other phospholipid fractions changed little. More pronounced changes occurred in brain mitochondria and liver phospholipids. The small changes in capillary endothelia with cal % EFA are in contrast to the great changes produced by a change in the linoleate/linolenate ratio. As the ratio is reduced, there is a progressive increase in the n-3 series in all phospholipid fractions.