The rats were divided into the following groups: 1) exposure to a 50 Hz magnetic field with 1 µT perpendicular to the north pole of the earth's magnetic field (n=6), 2) exposure to 1 µT parallel to the north pole (n=5), 3) exposure to 100 µT perpendicular to the north pole (n=6), 4) exposure to 100 µT parallel to the north pole (n=5).
The rats were examined for 5 days and urine was collected every night. For the first 2 days, the rats were kept in their cages without exposure to the magnetic field. The urine samples collected there were used as controls. On the 3rd day, the rats were exposed and afterwards examined for further 2 days without exposure.
|Chamber||rats were kept individually in metabolic cages, which were able to separate the urine from feces, food, and hair; the inner diameter of the cages was 20 cm; the height was 11 cm; the cages were made of plexiglass and glass, only the feeders were made of nonferrous stainless steel|
pair of double-wound coils embedded in molded epoxy resin to avoid vibration; the inner diameter of the coils was 42 cm; the distance between the two parallel, vertially mounted coils was 35 cm; the orientation of the magnetic field was horizontal; one of two animal cages was placed into the center of the coils, where flux density was 100 µT; the inhomogeneity of the magnetic field was less than 4% inside the cage; the perturbation around or in the stainless
steel feeder was less than 1%; the stray field in the other cage located 1.1 m away from the coils was 1 µT; the temperature increase of the coils was below 1°C during exposure; the geomagnetic field was 48 µT in the laboratory
No significant differences were found in the concentration of 6-sulfatoxy melatonin in urine during and after magnetic field exposure compared to before exposure.
The authors conclude that no effects of exposure of rats to a 50 Hz magnetic field on melatonin production could be found.