Effects of X-irradiation on protein synthesis in L5178Y and mouse fetal liver erythroid cells

The in vitro effects of X-irradiation on protein synthesis have been studied in murine luekemic lymphoblasts (L5178Y) and fetal mouse liver erythroid cells. Responses resulting from different total doses of irradiation, as well as from various dose rates, were noted. RNA and protein synthesis in L5178Y cells were unaffected. Protein synthesis was inhibited by irradiation of fetal mouse liver erythroid cells of 13- to 14-day gestation. Hemoglobin synthesis was apparently inhibited irreversibly as the result of an earlier inhibitory effect upon RNA synthesis. As the result of time studies and effects of actinomycin D, the hypothesis has been advanced that inhibition of hemoglobin synthesis, at least in fetal mouse liver erythroid cells, can be attributed to a primary effect of irradiation upon transcription of messenger RNA. The radiosensitivity in the two cell types was compared by measuring the responsiveness to actinomycin D.