ENDOCRINE FUNCTIONS IN YOUNG MEN EXPOSED FOR ONE NIGHT TO A 50-HZ MAGNETIC-FIELD - A CIRCADIAN STUDY OF PITUITARY, THYROID AND ANDRENOCORTICAL HORMONES

In recent years, some epidemiologic studies have suggested that extrem ely low frequency magnetic and electric fields might affect human heal th, and, in particular, that the incidence of certain types of cancer, depression, and miscarriage might increase among individuals living o r working in environments exposed to such fields. Work in our laborato ry studies whether and how changes in the electromagnetic environment might affect human health. The study presented here was designed to lo ok for possible effects of acute exposure to 50-Hz linearly polarized magnetic fields (10 mu T) on the hormones of the hypothalamic-pituitar y-thyroid and hypothalamic-pituitary-adrenal axes. Thirty-two young me n (20-30 years old) were divided into two groups (sham-exposed or cont rol group, and exposed group) of 16 subjects each. All subjects partic ipated in two 24-hour experiments to evaluate the effects of both cont inuous and intermittent(one hour ''off'' and one hour ''on'' with the field switched ''on'' and ''off'' every 15 seconds) exposure to linear ly polarized magnetic fields. The subjects were exposed to the magneti c field (generated by three Helmholtz coils per bed) from 2300 to 0800 while recumbent. Blood samples were collected during each session at 3 hour intervals from 1100 to 2000 and hourly from 2200 to 0800. Total urine was collected every 3 hours from 0800 to 2300 and then again at 0800. No significant differences were observed between sham-exposed a nd exposed men for any of the parameters measured: thyroid-stimulating hormone, follicle-stimulating hormone, luteinizing hormone, triiodoth yronine, thyroxine, free triiodothyronine, free thyroxine, thyroxine-b inding globulin, cortisol, 17-hydroxycorticosteroids (17-OH-CS) and TB K. These results suggest that acute exposure to either continuous or i ntermittent 50-Hz linearly polarized magnetic fields of 10 mu T does n ot affect, at least under our experimental conditions, these endocrine functions or their circadian rhythmicity in healthy young men.