The gene expression of neuron derived orphan receptor (NOR-1) which is suspected to control cell growth and differentiation was observed.
The experiments were repeated twice (5 mT, 50 Hz) or three times (400 mT, 50 Hz).
The exposed cells additionally were treated with forskolin, tetradecanoylphorbol acetate, protein kinase C-inhibitors (calphostin C, crocetin) and calcium channel blockers (nifedipine, dantrolen) in order to examine the effects of these chemical substances in exposed cells.
4 plates were used for each experiment; the experiment was repeated 2 or 3 times.
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Enhanced gene expression of NOR-1 was observed by exposure of CHO cells to an extremely low frequency magnetic field of 50 Hz at 400 mT, but not at 5 mT. The enhanced gene expression, reaching the maximum after 6 hours exposure, was transient and reduced to the control level after exposure to 400 mT extremely low frequency magnetic field for 24 hours.
The NOR-1 expression induced by treatment with forskolin and tetradecanoylphorbol acetate was further enhanced by the simultaneous treatment with 400 mT extremely low frequency magnetic field, in which the maximum response was at 3 hours exposure.
When cells were treated with an inhibitor of the protein kinase C and calcium channel blockers during the 400 mT extremely low frequency magnetic field exposure, the enhanced NOR-1 gene expression was not observed.