Magnetic Field Exposure and Pineal Melatonin Production (Mini-Review)

Abstract

The consequences of electromagnetic exposure for human health are receiving increasing scientific attention and have become the subject of a vigorous public debate. In the present study we evaluated the effect of magnetic field on pineal function in man and rat. Two groups ofWistar male rats were exposed to 50-Hz magnetic fields of either 1,10 or iOO 1lT. The first group wa exposed for 12 hand the second for 30 days (18 h per day). Short-term exposure depressed both pineal NAT activity and nocturnal serum melatonin concentration, but only with the highest intensity used (iOO flT). Long-term exposure to a magnetic field of 10 and 100 flT significantly depressed the nighttime peak of serum melatonin concentration and pineal NAT activity. Our re ult show that sinusoidal magnetic fjeld altered the production of melatonin through inhibition of pineal NAT activity. Both the duration and the intensity of exposure played an important role in thi effec!. In the second step of this study, 32 young men (20-30 years old) were divided into two groups (control group, i. e., ham-exposed: 16 subjects; exposed group: 16 subject). The ubject were exposed to the magnetic fjeld from 2300 h to 0800 h (i. e., for 9 h) while Iying down. In one experiment the exposure was continuous; in the se co nd one, the magnetic field wa intermittent. No ignificant differences were observed between sham-exposed (control) and exposed men for serum melatonin, 6-sulfatoxymelatonin, immunological and hematological variables, and serum cortiso!. This study suggests that, at least und er the conditions used in our experiment, acute exposure to either a continuous or an intermittent 50-Hz magnetic fjeld of 10 flT does not affect plasma melatonin concentration or its circadian rhythm in healthy young men.