[Influence of small doses of fractionated X-ray radiation on the activity of histone-specific proteases and the content of malonic dialdehyde in chromatin of the cells of rat liver]
The fractionated X-ray irradiation resulted in accumulation of malonic dialdehyde (MDA) in chromatin of the cells of rat liver and activation of nuclear endogenous histon-specific proteases. Seven days after the termination of irradiation, the activity of the nuclear proteases returned to the control level and the MDA level remained 10% above the control parameter. The correlation (r = 0.71) of the processes of MDA accumulation in chromatin and activation of histon-specific proteases in the cells of rat liver after the termination of irradiation showed that these processes were coupled. Transplantation of Guerin's carcinoma to the irradiated animals caused the changes in nuclear proteolysis of the histones and MDA level in chromatin of the tumor-carrier liver cells, which lessened the influence of preliminary X-ray irradiation on rats.