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The effect of exposure to 100 or 50 microT, 50 Hz, vertical magnetic field on the excretion of 6-sulphatoxymelatonin (6SM) in the nocturnal urine of rats was studied. Twelve male Wistar rats were kept under 12:12 hr light:dark conditions. The nocturnal urine of animals was collected in metabolic cages over 4 consecutive weeks. The concentration of 6SM in the rat urine was measured by 125I radioimmunoassay and normalized to creatinine concentration. After the first week of urine collection, 6 rats were exposed to 100 microT or 50 microT flux density magnetic fields (MF) for 8 hr daily for 1 week. It was found that the excretion of the primary metabolite of melatonin in the urine, 6SM, did not show statistically significant changes during and after magnetic field exposure.

This study evaluated the effect of sinusoidal 50 Hz magnetic field on the basal and human chorionic gonadotropin (hCG)-stimulated testosterone (T) production of 48-h mouse Leydig cell culture. The luteinizing hormone (LH) analog hCG was used to check the T response of the controls and to evaluate the possible effect of the applied magnetic field on the steroidogenic capacity of the exposed cells. Leydig cells were obtained from the testes of 35- to 45-g CFLP mice and isolated by mechanical dissociation without enzyme treatment. The cell cultures were exposed to sinusoidal 50 Hz 100 microT (root mean square) AC magnetic field during the entire time of a 48-h incubation. Testosterone content of the culture media was measured by radioimmunoassay. In cultures exposed to the magnetic field, a marked increase of basal T production was found (P < .05), compared with the unexposed controls, whereas no significant difference was seen between the exposed or unexposed cultures in the presence of maximally stimulating concentration of hCG. These findings demonstrate that sinusoidal 50 Hz 100 microT magnetic fields are able to stimulate the basal T production of primary mouse Leydig cell culture, leaving the steroidogenic responsiveness to hCG unaltered.

The effect of a 50 Hz, vertical magnetic field on the excretion of urinary 6-sulphatoxymelatonin (aMT6s) of male and female Wistar rats was studied in a self-controlled experiment. Twenty rats were kept in metabolic cages under 9:15 h light:dark conditions. The urine of the animals was collected twice per day for 5 consecutive days. The concentration of aMT6s in the rat urine was measured by 125I radioimmunoassay. The rats were exposed to 5 and 500 microT flux density for 24 h. The excretion of urinary aMT6s did not show significant changes during or after magnetic field exposure.