RADIOBIOLOGY OF A DIFFERENTIATING CELL SYSTEM INVITRO

Friend erythroleukemia cells (FELC) [mouse] in vitro were used to examine the effects of ionizing radiation on differentiation and proliferation of mammalian cells. Apparently X-rays can affect differentiation in 2 different ways. X-rays inactivate the ability of these cells to respond to an external trigger of differentiation, e.g., dimethyl sulfoxide. X-rays themselves trigger a partial differentiation response, in the absence of any other external trigger. The radiation-induced lesions leading to these 2 end-points are not repaired in split-dose experiments, unlike those lesions which lead to loss of cell proliferative capacity. The profile of solube FELC proteins, as analysed by isoelectric focusing, was also affected by irradiation. These effects of ionizing radiation on the expression of genetic information in mammalian cells have important implications for radiobiology, particularly at low doses where acute lethal effects are minimal.