Continuous Irradiation of a Murine Lymphoma Line P388F <i>in Vitro</i>

Abstract

SummaryThe response of the P388F murine lymphoma in vitro to continuous irradiation at dose-rates between 60 and 210 rad/day from tritiated water in the culture medium has been studied. The population doubling time of the cultures increases with increasing dose-rate. Labelling experiments with 3H thymidine indicated some increase in cell-cycle time and also the existence of non-dividing cells. Cloning techniques demonstrated that not all cells capable of synthesizing DNA have the capacity for indefinite reproduction. A model which accounts for the results is discussed. It proposes that, as a result of the continuous irradiation, at each cell division a proportion of the daughter cells lose their reproductive integrity but may nevertheless undergo several divisions before becoming completely sterile.