Effect of 60 Hz magnetic field exposure on c-fos expression in stimulated PC12 cells.
Rat pheochromocytoma PC12 cells have been treated with nerve growth factor (NGF) at final concentrations of 2, 4, 8, and 16 ng/ml, and then were exposed to 60-Hz, sinusoidal magnetic fields (MF) of 12.5, 25, 50, and 100 microT (rms) for 30 min. Transcript levels for both c-fos and glyceraldehyde-3 -phosphate dehydrogenase were determined by Northern blot analysis using 32P-labeled cDNA probes. No change in c-fos expression was measured at any condition employed. Treatment of PC12 cells with a combination of agents (NGF, forskolin, and tetradecanoylphorbol acetate [TPA]) increased c-fos expression over that detected with NGF alone. MF exposure of cells treated with the three-agent regimen produced two outcomes, either no change or a doubling of c-fos expression. In subsequent experiments, cells were treated with NGF, NGF + forskolin + TPA, or pre-treated with anisomycin and then treated with NGF + forskolin + TPA. It was determined that MF exposure, like superinduction with anisomycin, increased c-fos expression only in cultures which were not yet exhibiting maximal c-fos expression. It is hypothesized that MF exposure, like anisomycin, may alter the activity of key intracellular protein kinases.
Campbell-Beachler
M
M
Pettis VA Medical Center, Loma Linda, CA 92357, USA.
Ishida-Jones
T
T
Haggren
W
W
Phillips
J L
JL
D000818:Animals; D015152:Blotting, Northern; D005576:Colforsin / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004574:Electromagnetic Fields / Q000009:adverse effects*; D015972:Gene Expression Regulation, Neoplastic; D009414:Nerve Growth Factors / Q000494:pharmacology*; D016716:PC12 Cells; D010673:Pheochromocytoma / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D051381:Rats; D013997:Time Factors
D009414:Nerve Growth Factors; D016760:Proto-Oncogene Proteins c-fos; D005576:Colforsin