EXPOSURE TO ELECTRIC AND MAGNETIC (EM) FIELDS INCREASES TRANSCRIPTS IN HL-60 CELLS - DOES ADAPTATION TO EM FIELDS OCCUR

Increased levels of c-myc and histone H2B transcripts are detectable after 4 min of exposure of cells to a 60 Hz sinusoidal magnetic field (80 muT). When cells are continuously exposed to the same field, transcript levels for both c-myc and histone H2B remain significantly elevated over control values for at least 2 h, but return to control levels by 4 h. In cells exposed for 20 min, and then removed from the EM field for time periods up to 4 h, a similar pattern of transcript levels was observed. Results from the two sets of exposure conditions show that the responsive time period in the cell following exposure to continuous 60 Hz sine waves is rapid and that neither longer exposures nor removal from the signal significantly affects the pattern or duration of the response.