Sensitivity to X-irradiation in relation to cell size of CHO cells synchronized in early G1.

A population of line CHO Chinese hamster cells was synchronized by mitotic selection and allowed to enter early G1, after which the largest and smallest cells in the population were sorted, irradiated, and their viability determined. Despite sizeable differences in volume, metabolic capability and cell cycle progression rates, an equivalent level of survival was obtained for the two populations, indicating that the factors responsible for the volume, metabolic and progression heterogeneity do not contribute greatly to radiation sensitivity.