ACTION OF 50 HZ MAGNETIC-FIELDS ON CAMP CONTENT IN SV40-3T3 CELLS - DEPENDENCE ON FLUX-DENSITY AND EXTRACELLULAR CALCIUM

5 min exposure of SV40-3T3 cell monolayers to a homogeneous sinusoidal 50 Hz magnetic field raised at 2 mT flux density the intracellular cy clic AMP concentration to 115% relative to the controls (p = 0.01). At flux densities below and above 2 mT, the changes in cAMP level seemed to be less pronounced or even converted into the opposite direction. The effect at 2 mT was seen both, in culture medium and in buffer, but not when cells were exposed in calcium-free buffer. The 'non-linear' flux density-effect relationship 'windowing' at 2 mT is interpreted to be due to a rise in cAMP caused by the induced electric field which, at higher flux densities, may be counteracted by direct magnetic coupl ing to calcium ion transport. (C) 1997 Elsevier Science S.A.