EFFECT OF MAGNETIC FIELD ON GENE EXPRESSION AND NUTATION INDUCTIC

将PC12-VG细胞暴露于极低频率磁场(ELFMF)中，可增强Forsklin处理细胞所刺激的β-半乳糖苷酶基因的表达。用PKC的特异性抑制剂calphostin C以及钙通道阻滞剂硝苯地平和丹托伦处理细胞，ELFMF的增强作用被抑制。当在培养过程中的不同时间给予ELFMF时，在4h的Forsklin处理的第一个小时内出现增强。我们推测，在Forsklin治疗的早期反应中，PC12-VG细胞暴露于ELFMF影响细胞信号转导，导致基因表达增强。另一方面，50 Hz和400mT的ELFMF暴露诱导了人黑色素瘤MeWo细胞的次黄嘌呤-鸟嘌呤磷酸核糖转移酶基因突变。随着暴露时间的延长和诱导电流强度的增加，突变频率均有所提高。ELFMF暴露可增强X射线诱发的突变。在ELFMF暴露期间，当DNA复制被抑制时，突变频率没有显著增加。DNA复制错误被怀疑是导致ELFMF暴露产生突变的原因。

Exposure of PC12-VG cells to an extremely low frequency magnetic field (ELFMF) enhanced the beta-galactosidase gene expression stimulated by teatment of the cells with forskolin. The enhancing effect of the ELFMF was inhibited by treatment of the cells with a specific inhibitor of PKC,calphostin C,as well as with the Ca^<2+> entry blockers nifedipin and dantrolen. Enhancement appeared within the first hour of a 4h forskolin treatment when the ELFMF was given at different times during culture. We speculate that exposure of PC12-VG cells to an ELFMF during the early response to forskolin treatment affects cell signal transduction, resulting in enhanced gene expression.On the other hand, an exposure to ELFMF of 50 Hz and 400mT induced mutations in the hypoxanthine-guanine phosphoribosyl transferase gene of human melanoma MeWo cells. The mutation frequency was enhanced both by increasing the exposure period and the induced current intensity. Mutations induced by X-rays were enhanced by ELFMF exposure. No significant increase in mutation frequency occurred when DNA replication was inhibited during ELFMF exposure. DNA replication error is suspected to cause the mutations produced by ELFMF exposure.