Hyperthermia-induced increase in potassium transport in Chinese hamster cells. Appendix: Application of compartmental analysis to the determination of ion fluxes in Chinese hamster cells

The effect of hyperthermia (42 degree C) on K super(+) transport has been examined by monitoring the uptake of super(42)KCl by Chinese hamster (line CHO) cells at both 37 degree and 42 degree C as well as 37 degree C following a 30-min treatment at 42 degree C. Early studies showed that CHO cells exhibit two components of uptake at both 37 degree and 42 degree C. The results of this study showed that both components of influx at 42 degree C are increased over influx at 37 degree C; the increase is significant (by an average 68% for the rapid component and 55% for the slow component); and the increase is due entirely to an increase in active transport. The increased active transport is both immediate and quickly reversible when cells are returned to 37 degree C; resumption of cell division is delayed for several additional hours, indicating that changes in potassium transport are not directly responsible for the prolonged delay in cell division.