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 effects of magnetic field on pineal function in man and rat.

Two groups of Wistar male rats were exposed to 50-Hz magnetic fields of either 1,10 or 100 μT. The first group was exposed for 12 h and 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 (100 μT). Long-term exposure to a magnetic field of 10 and 100 μT significantly depressed the nighttime peak of serum melatonin concentration and pineal NAT activity. Our results show that sinusoidal magnetic field altered the production of melatonin through inhibition of pineal NAT activity. Both the duration and the intensity of exposure played an important role in this effect.

In the second step of this study, 32 young men (20–30 years old) were divided into two groups (control group, i.e., sham-exposed: 16 subjects; exposed group: 16 subjects). The subjects were exposed to the magnetic field from 2300 h to 0800 h (i.e., for 9 h) while lying down. In one experiment the exposure was continuous; in the second one, the magnetic field was intermittent. No significant differences were observed between sham-exposed (control) and exposed men for serum melatonin, 6-sulfatoxymelatonin, immunological and hematological variables, and serum cortisol.

This study suggests that, at least under the conditions used in our experiment, acute exposure to either a continuous or an intermittent 50-Hz magnetic field of 10 μT does not affect plasma melatonin concentration or its circadian rhythm in healthy young men.