Urinary 6-sulphatoxymelatonin excretion is increased in rats after 24 hours of exposure to vertical 50 Hz, 100 μT magnetic field

The effect of exposure to a 50 Hz, vertical magnetic field on the excretion of urinary 6-sulphatoxymelatonin (aMT6s) of rats was studied in a self-controlled experiment. Ten male Wistar rats were kept under 9:15 h light: dark conditions in metabolic cages. The rats were exposed to 1.0 or 100 microT flux density for 24 h. The excretion of aMT6s, which is the primary metabolite of melatonin in the urine, did not show a statistically significant decrease, as measured by 125I radioimmunoassay, during or after magnetic field exposure of rats to either flux density. At 100 microT flux density, the increase of aMT6s excretion on the day after exposure was statistically significant (P < .02), compared with the value under exposure, but was not significant compared with the baseline values before exposure.