[en] Biosynthesis of globulin fraction, histones and acid proteins of nuclei of liver, spleen, thymus and bone marrow has been studied 60 min, 2, 3, 4, 5, 6, 7, 8, 9 and 24 hr following the exposure of rats to 600 R. Irradiation has been found to modify the biosynthesis of all nuclear proteins in the liver 8 and 9 hr after irradiation. In the spleen, thymus and bone marrow, the nuclear protein biosynthesis was inhibited throughout the entire period of observation, the biosynthesis of basic nuclear proteins being impaired to a greater extent