Medical/biological study (experimental study)

Exposure of female rats to a 100-microT 50 Hz magnetic field does not induce consistent changes in nocturnal levels of melatonin med./bio.

By: Loscher W, Mevissen M, Lerchl A

Published in: Radiat Res 1998; 150 (5): 557-567

Aim of study (acc. to author)

To investigate the effect of a 50 Hz/100 µT magnetic field exposure on melatonin levels in DMBA-treated rats.

Background/further details

Several experimental attempts were accomplished: A) Long term magnetic field exposure (13 weeks) with or without DMBA treatment and determination of nocturnal melatonin levels in pineal gland and blood serum 5 hours after the onset of dark phase. B) Effects of a two week magnetic field exposure on plasma melatonin levels determined 3, 5, and 6 hours after the onset of dark phase. C) Effects of different magnetic field exposure times (i.e. 4, 8, and 13 weeks) on plasma melatonin determination at different time points (5 and 6 hours after the onset of dark phase. D) Effects of short term magnetic field exposure (i.e. 1 day, 1 week, 2 weeks) on plasma melatonin levels. Several experimental attemptes were accomplished: A) Long term magnetic field exposure (13 weeks) with or without DMBA treatment and determination of nocturnal melatonin levels in pineal gland and blood serum 5 hours after the onset of dark phase. B) Effects of a two week magnetic field exposure on plasma melatonin levels determined 3, 5, and 6 hours after the onset of dark phase. C) Effects of different magnetic field exposure times (i.e. 4, 8, and 13 weeks) on plasma melatonin determination at different time points (5 and 6 hours after the onset of dark phase. D) Effects of short term magnetic field exposure (i.e. 1 day, 1 week, 2 weeks) on plasma melatonin levels.

Endpoint

endocrine changes: melatonin levels

Exposure

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: 24 h/day, 7 days/week, over 13 weeks	magnetic flux density: 100 µT effective value

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	24 h/day, 7 days/week, over 13 weeks
Additional info	horizontal polarization

Exposure setup

Exposure source	Merritt coils coils: 26 turns outer, 11 turns inner coils, 1 m side length, 1,5 mm² copper wire

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	100 µT	effective value	-	-	-

Additional parameter details

stray field 0.1 µT 50 Hz field in laboratory: 0.03-0.04 µT earth MF: 16 µT parallel, 36 µT perpendicular to MF

Exposed system:

Methods Endpoint/measurement parameters/methodology

endocrine changes: melatonin levels in pineal gland and blood serum and plasma (radioimmunoassay)

Investigated system:

isolated bio./chem. substance

Investigated organ system:

endocrine system

Time of investigation:

after exposure

Main outcome of study (acc. to author)

No consistent of the magnetic field exposure up to 13 weeks on nocturnal melatonin levels in the pineal gland or blood serum could be demonstrated by this study.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Bundesministerium für Umwelt, Naturschutz und Reaktorsicherheit (Federal Ministry of the Environment, Nature Conservation, and Nuclear Safety), Germany
Department of Energy, USA

Seifpanahi-Shabani H et al. (2016): Long-term Exposure to Extremely Low Frequency Electromagnetic Field and Melatonin Production by Blood Cells
Dyche J et al. (2012): Effects of power frequency electromagnetic fields on melatonin and sleep in the rat
Davis S et al. (2006): Effects of 60-Hz magnetic field exposure on nocturnal 6-sulfatoxymelatonin, estrogens, luteinizing hormone, and follicle-stimulating hormone in healthy reproductive-age women: results of a crossover trial
Gobba F et al. (2006): No association between occupational exposure to ELF magnetic field and urinary 6-sulfatoximelatonin in workers
Chacon L (2000): 50-Hz Sinusoidal Magnetic Field Effect On In Vitro Pineal N-Acetyltransferase Activity
Heikkinen P et al. (1999): Chronic exposure to 50-Hz magnetic fields or 900-MHz electromagnetic fields does not alter nocturnal 6-hydroxymelatonin sulfate secretion in CBA/S mice
Selmaoui B et al. (1999): Age-related differences in serum melatonin and pineal NAT activity and in the response of rat pineal to a 50-Hz magnetic field