Effects of static magnetic fields on membrane permeability of a cultured cell line

To clarify the effects of magnetic fields on plasma membrane permeability of "living cells", we measured the accumulation and efflux of adriamycin (ADR) in a cell line, TALL-1, using flow cytometric techniques. The amount of ADR accumulated in the cells for 15 minutes under a static magnetic field (0.4 Tesla(T), 1T = 10000 gauss) was less than 5-10% that in the control cells without magnetic fields within a temperature range of 41-46 degrees C corresponding to the phase transition temperature. It is interesting that ADR efflux from magnetic field-exposed cells increased compared with unexposed cells at 41-44 degrees C. These results suggest that lipid clustering, which occurs at the phase transition temperature, may take place in "living cells" as well as in artificial membranes and play an important role in increasing the ADR efflux from the cell membrane under magnetic fields.