Cell Size Following Irradiation in Relation to Cell Cycle

The cell volume of Ehrlich ascites tumour cells was studied following a radiation dose of 5.0 Gy. The cell volume increased 12 to 30 hours after irradiation by about 20 per cent, was normal at about 50 hours, and increased again at 72 hours. In order to explain these changes the composition of the cells in cell cycle was studied. In addition, the cell volume of irradiated cells from the various parts of the cell cycle, separated by centrifugal elutriation, was measured. The changes in the mean cell volume of unseparated cells could be explained by variations in the cell cycle composition of the cell population. Irradiated cells from the various parts of the cell cycle did not deviate from the volume of non-irradiated cells. The cell volume doubled during the cell cycle. This increase was, however, not linear.