Nonthermal 60 Hz sinusoidal magnetic‐field exposure enhances ⁴⁵Ca²⁺ uptake in rat thymocytes: dependence on mitogen activation

The effect of a 60 Hz sinusoidal magnetic field of nonthermal intensity on Ca²⁺ metabolism in rat thymic lymphocytes (thymocytes) was assessed in resting cells and in cells activated with the mitogen Concanavalin A (Con A). A 60 min exposure at 37°C to an induced electric field of 1.0 produced an average 2.7-fold increase in Con A-dependent ⁴⁵Ca²⁺ -uptake compared to non-exposed, isothermal control cells. In contrast, ⁴⁵Ca²⁺ uptake remained unaltered during exposure of resting thymocytes. It was also found that thymocytes with a diminished ability to mobilize Ca²⁺ in response to Con A were most sensitive to the 60 Hz magnetic field. Although the precise mechanism of field interaction is at present unknown, modulation of Ca²⁺ metabolism during cell activation may represent a common pathway for field coupling to cellular systems.