RNA metabolism, DNA damage and cellular resistance to X-rays: investigations in chick embryo and rat cells.
Three hours after X-irradiation in vivo with 8 Gy the in vitro incorporation of [3H]uridine into total RNA of liver(L)- and brain(B)-cells of the chick embryo was reduced to 77% and 90%, respectively; the mRNA fraction was strongest inhibited. Under the same conditions, protein synthesis of L-cells declined to 62%, while protein synthesis of B-cells was not influenced. RNA and protein metabolism was not altered following X-irradiation in vitro (1.75-56 Gy). Compared to thymic- and splenic cells of the rat, chicken embryo cells exhibited higher constitutive poly(adenosine diphosphate-ribose)polymerase activity and lower X-irradiation-induced DNA damage. Whereas the slight inhibition of RNA and protein synthesis by X-irradiation in ovo may be an abscopal and/or secondary phenomenon reflecting DNA and/or cellular damage, the present investigations comprising various cell types argue for an efficient DNA repair in chicken embryo cells caused, at least partly, by a high constitutive activity of DNA repair proteins.
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Institut für Pharmakologie, Toxikologie und Pharmazie, Universität München, Bundesrepublik Deutschland.
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D000818:Animals; D001921:Brain / Q000196:embryology / Q000502:physiology / Q000528:radiation effects*; D002470:Cell Survival / Q000528:radiation effects; D002478:Cells, Cultured; D002642:Chick Embryo; D004247:DNA / Q000528:radiation effects*; D004249:DNA Damage; D004622:Embryo, Mammalian; D005260:Female; D007700:Kinetics; D008099:Liver / Q000196:embryology / Q000502:physiology / Q000528:radiation effects*; D011247:Pregnancy; D012313:RNA / Q000378:metabolism / Q000528:radiation effects*; D051381:Rats; D011919:Rats, Inbred Strains; D013154:Spleen / Q000166:cytology / Q000528:radiation effects; D013601:T-Lymphocytes / Q000166:cytology / Q000528:radiation effects; D014316:Tritium; D014529:Uridine / Q000378:metabolism; D014965:X-Rays
D014316:Tritium; D012313:RNA; D004247:DNA; D014529:Uridine