Activation of lipid metabolism of nuclei and chromatin in thymocytes of rats subjected to chronic low dose intensity gamma-irradiation.

Contents and radioactivity (as incorporation of [2-14C]acetate) of thymocyte nuclear and chromatin lipids were investigated in rats subjected to chronic gamma-irradiation in a dose 10 Gy at the intensity of 12.9 cGy/day. The incorporation of label into total fraction of lipids of nuclei and chromatin and into total phospholipid fraction of thymocyte nuclei increased. However, in the whole cells differences in radioactivity of these fractions were not found. The amount of fatty acids in thymocytes from irradiated rats was decreased but synthesis of fatty acids was activated. The amount of fatty acids in nuclei and chromatin remained unchanged compared with control, whereas radioactivity was significantly higher than in the whole cells. In irradiated thymocytes the amounts of phosphatidylserine in nuclei and phosphatidylserine and phosphatidylinositol in chromatin were increased. The incorporation of [2-14C]acetate into proteins increased in thymocytes of irradiated rats. The role of lipid metabolism in genome functioning is discussed.