[Postradiation activation of proteinases associated with the hepatocyte nuclear matrix in rats]

Proteinase activity of the nuclear matrix of rat hepatocytes was 7-8-times as high as that of initial nuclei. Activity of nuclear matrix proteinases was optimum at pH 8-9. Proteolytic activity associated with the nuclear matrix, increased by 1.4-2.8 times 2 h following irradiation with doses from 5 to 30 Gy. Cycloheximide, a protein synthesis inhibitor, administered to animals failed to suppress the radiation-induced increase of proteinase activity of the nuclear matrix.