The effect of the x-ray irradiation of rats on the NAD-pyrophosphorylase and poly(ADP-ribose)polymerase activities of brain nuclei and on the NAD content in nerve tissue

A study was made of the influence of X-irradiation of rats with various doses on NAD-pyrophosphorylase and poly(ADP-ribose) polymerase activity of brain nuclei. It was shown that X-radiation was ineffective with regard to NAD-pyrophosphorylase activity of nuclei and increased their poly(ADP-ribose) polymerase activity. Stimulation of poly(ADP-ribose) polymerase activity of nuclei was a function of radiation dose and correlated with the decrease in the NAD content of nervous tissue. It was found that mainly nonhistone proteins were ADP-ribosylated in nuclei of both irradiated and nonirradiated rats.