ENHANCED NOR-1 GENE-EXPRESSION BY EXPOSURE OF CHINESE-HAMSTER CELLS TO HIGH-DENSITY 50 HZ MAGNETIC-FIELDS

Enhanced expression of neuron derived orphan receptor (NOR-1) gene was observed by exposure of Chinese hamster ovary K1 (CHO-K1) cells to an extremely low frequency magnetic field (ELFMF) of 50 Hz at 400 mT, bu t not at 5 mT. The enhanced expression, reaching the maximum at 6 h, w as transient and reduced to the control level after exposure to 400 mT ELFMF for 24 h. The NOR-1 expression induced by treatment with forsko lin and TPA was further enhanced by the simultaneous treatment with 40 0 mT ELFMF, in which the maximum response was at 3 h. The NOR-1 expres sion by these treatments was induced more earlier than that by 400 mT ELFMF alone. When cells were treated with an inhibitor of the protein kinase C (calphostin C or crocetin) and Ca2+ entry blockers (nifedipin and dantrolen) during the 400 mT ELFMF exposure, the enhanced NOR-1 e xpression was not observed. Exposure of CHO-K1 cells to the high-densi ty 400 mT ELFMF may affect the signal transduction in the cells, resul ting in the enhanced NOR-1 gene expression.