Effect of essential fatty acid deficiency on the synthesis and turnover of myelin lipid

The metabolism of myelin glycerophospholipids as a function of essential fatty acid (EFA) deficiency was studied in rats. Mothers were fed a lipid‐free diet from the eighth day of pregnancy throughout the suckling period. Pups were continued on the diet after weaning. Control mothers and pups were fed the same diet as experimental rats plus 3% corn oil for the same periods. Pups fed the lipid‐free diet had lower total body weight, brain weight, and total myelin phospholipid levels than controls. At 17 days of age, each rat pup was injected with a mixture of [3H]‐glycerol and [1‐14C]‐acetate and were killed up to 80 days after injection. Lipids were extracted from isolated myelin. The 3H/14C ratio for choline, serine, and ethanolamine glycerophospholipids decreased more slowly in experimental rats than in controls, suggesting an alteration in either the turnover of myelin phospholipids or the recycling of phospholipids into myelin. Radiolabelled acyl moieties were isolated from myelin lipids and separated according to the degree of unsaturation. Acyl groups with three double bonds, presumably 20:3 (ω−9), isolated from EFA‐deficient rats appeared to be synthesized from a long‐lived pool of precursor. The relative synthesis of other unsaturated acyl moieties appeared to be the same in both groups of rats. These results indicate that EFA deficiency affects myelin metabolism.