Levels of polyunsaturated fatty acids in lymphocytes of rats fed on diets varying in polyunsaturated fatty acid content.

1. When weanling rats were fed on a diet containing 0.1 g/kg of the diet as polyunsaturated fatty acid, it was found that after 2 weeks the level of linoleate in the lymphocyte lipids was 56 mg/g total fatty acids, as compared with a level of 138 mg/g in rats on a normal diet (P less than 0.005). Similar levels were obtained from rats which had been fed for up to 16 weeks on the deficient diet, but in a group killed after 28 weeks on the diet level was found to be only 20 mg/g total fatty acids. The arachidonate level was found to be approximately 220 mg/g total fatty acids, regardless of whether the rats were fed on a diet deficient in linoleate for up to 16 weeks or on a normal diet. In the group of rats killed after 28 weeks on the linoleate deficient diet, however, the arachidonate level was only 60 mg/g total fatty acids. 2. Percentage values for total fatty acids are given for plasma, adipose tissue, and lymphocytes for rats on normal and experimental diets. 3. Scatter diagrams of the levels of linoleate v. arachidonate in the lymphocyte total fatty acids showed no correlation between the levels of the two acids (r 0.05), but similar plots of linoleate and oleate levels showed an inverse correlation (r -0.68).