title: Relative responses of an X-ray-resistant hybrid cell-line and its parent line to X-irradiation, ultraviolet light, actinomycin D and cordycepin.
abstract: Using colony formation as an assay, a rat-mouse hybrid cell-line (HD1) and one of its parent lines (H4) have been studied as to their abilities to survive exposure to ionizing radiation, ultraviolet light, and the drugs actinomycin D and cordycepin. HD1 cells are more resistant than H4 to ionizing radiation, actinomycin D and cordycepin. Both cell lines respond similarly to ultraviolet light. When both cell-lines were co-treated with actinomycin D or cordycepin, the toxic effect of ionizing radiation was enhanced, whereas that of ultraviolet light (U.V.L.) was unchanged. The data suggest that RNA synthesis is more important immediately after irradiation with X-rays than with U.V.L. and that cells resistant to the toxic effect of ionizing radiation are also resistant to the toxicity induced by inhibitors of RNA synthesis.
mesh_terms: D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D003609:Dactinomycin / Q000494:pharmacology*; D003839:Deoxyadenosines / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D006822:Hybrid Cells / Q000187:drug effects* / Q000528:radiation effects*; D011839:Radiation, Ionizing; D014466:Ultraviolet Rays; D014965:X-Rays
chemical_list: D003839:Deoxyadenosines; D003609:Dactinomycin