Abstract
Several studies have reported that electromagnetic fields suppress nocturnal melatonin production in animals. In this study we investigated whether chronic (over 17 months) exposure to vertical 50-Hz magnetic fields with regularly varying intensity (1.3,13, and 130μT; 24 h/day) affects nocturnal 6-hydroxymelatonin sulfate (6-OHMS) production in female CBNS mice. The effects of 900 MHz radiofrequency radiation (90 midday) were also studied, using either continuous radiation with a specific absorption rate (SAR) of 1.5 W/kg or pulsed radiation with a pulse repetition rate of 217 MHz and a SAR (average) of 0.35 W/kg. Twenty-four mice per group were kept in metabolic cages (three animals per cage) for two nights (from 7 PM to 7 AM) with a 1-week intewal, and urine was collected. Urinary concentration of 6-OHMS, the main metabolite of melatonin, was determined by radio-immunoassay. Neither the extremely low-frequency magnetic field nor the radiofrequency radiation affected excretion of 6–OHMS in nocturnal urine.