Is the NAD-poly (ADP-ribose) polymerase system the trigger in radiation-induced death of mouse thymocytes?
Agents that induce DNA strand breaks evoke a drop in the NAD content in mouse thymocytes. A decrease in the endogenous NAD content that occurs immediately after gamma-irradiation of thymocytes is entirely attributed to the activation of poly(ADP-ribosylation). The addition of 5 mM benzamide before irradiation prevents the postirradiation drop of the NAD level but has no effect on chromatin degradation and cell death. In contrast to liver nuclei, pre-incubation of mouse thymic nuclei with NAD had no effect on the subsequent chromatin endonucleolysis by Ca2+/Mg2+-dependent endonuclease. It is suggested that the NAD-poly(ADP-ribose) polymerase system is probably not the trigger in the radiation-induced programmed death of mouse thymocytes, but may merely be indicative of the radiation response of these cells.
Denisenko
M F
MF
Institute of Biophysics, U.S.S.R. Department of Health, Moscow.
Soldatenkov
V A
VA
Belovskaya
L N
LN
Filippovich
I V
IV
D000818:Animals; D001550:Benzamidines / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D002843:Chromatin / Q000187:drug effects / Q000528:radiation effects; D004247:DNA / Q000187:drug effects; D004249:DNA Damage; D005720:Gamma Rays; D008297:Male; D051379:Mice; D009243:NAD / Q000378:metabolism*; D009244:NAD+ Nucleosidase / Q000378:metabolism; D009536:Niacinamide / Q000494:pharmacology; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D013601:T-Lymphocytes / Q000201:enzymology / Q000528:radiation effects*
D001550:Benzamidines; D002843:Chromatin; D009243:NAD; D009536:Niacinamide; D004247:DNA; D011065:Poly(ADP-ribose) Polymerases; D009244:NAD+ Nucleosidase; C032157:benzamidine