Superimposition of an Incoherent Magnetic Field Eliminated the Inhibition of Hormone Secretion Induced by a 50-Hz Magnetic Field in Human Villous Trophoblasts <i>in vitro</i>

The effects of exposure to a sinusoidal 50-Hz magnetic field (MF) and an incoherent (noise) MF on hormone secretion in human first trimester villous trophoblasts were investigated. Trophoblasts were isolated from more than 30 first trimester human chorionic villi of 8-10 weeks gestation. They were cultured and exposed to MFs for different durations. The concentrations of human chorionic gonadotropin (hCG) and progesterone in culture medium were measured by electrochemiluminescence immunoassay. The results showed that exposure of the villous trophoblasts to a 50-Hz MF at 0.4 mT (milli Tesla) for 72 hrs could significantly inhibit the secretion of hCG and progesterone, whereas exposure to an incoherent MF (frequency range between 30 to 90 Hz) with the same conditions did not significantly affect the secretion. However, when the incoherent MF was superimposed on the 50-Hz MF and the cells were exposed to both fields simultaneously, no significant change in hormone secretion was observed. Based on these results, we concluded that 50-Hz MF exposure for 72 hrs could inhibit the hormone secretion of trophoblasts, and an incoherent MF of equal intensity could completely eliminate the effects induced by the 50-Hz MF.