A quantitative and qualitative study of the lipid composition of rat weaning and adult thymus tissue.

The principle aim of this investigation was to compare the lipid composition of the weaning and the adult involuted thymus. In its trglyceride deposition the response of the involuted thymus paralleled that of adipose tissue in that approximately 100 mg/g of triglyceride were evident among the phospholipid concentrations of weanling and adult thymus tissue, but the total cholesterol concentration did increase significantly in the adult rat thymus. Gas-liquid chromatographic analyses of fatty acids indicating that the involuting thymus tissues contained more unsaturated than saturated fatty acids--even to a greater degree than adipose tissue. Sex differences were found to be negligible. The possibilities of a thymus cholesterol synthesizing system, a fatty-acid desaturation system, or thymic humoral influences upon fatty-acid desaturation are proposed.