[Mechanism of chromatin degradation in thymocytes of irradiated rats. 6. Postradiation changes in the activity of poly(ADP-riboso)-polymerase]. / Mekhanizm degradatsii khromatina v timotsitakh obluchennykh krys. Soobshchenie 6. Postradiatsionnye izmeneniia aktivnosti poli(ADF-ribozo)-polimerazy.

ABSTRACT

A biphase change in poly (ADP-ribose) polymerase activity of the thymocyte chromatin was observed after 10 Gy irradiation of rats during the first minutes the incorporation of 14C-NAD increased by 40% then started decreasing to make 110, 60 and 35% after 1, 2 and 3 h, respectively. Irradiation of rat thymus chromatin in vitro sharply decreased poly (ADP-ribose) polymerase activity. The possible role of changes in the poly (ADP-ribose) synthesis in the activation of nuclear Ca/Mg-dependent endonuclease and in the postirradiation degradation of the thymocyte chromatin is discussed.