Medical/biological study (experimental study)

Long-term Exposure to Extremely Low Frequency Electromagnetic Field and Melatonin Production by Blood Cells med./bio.

By: Seifpanahi-Shabani H, Abbasi M, Salehi I, Yousefpour Z, Zamani A

Published in: Int J Occup Environ Med 2016; 7 (3): 193-194

Aim of study (acc. to author)

The effects of exposure of rats to a 50 Hz magnetic field on the melatonin production of blood cells should be investigated.

Background/further details

It is assumed that melatonin is mainly secreted from the pineal gland and the effects of ELF-EMF on the production of melatonin from the pineal gland have been investigated during past decades. However, melatonin can also be produced by bone marrow and immune system cells in the blood.
Rats were divided into 2 groups (n=20 each): exposure group and control group.

Endpoint

endocrine changes: melatonin production of rat blood cells

Exposure

- 50 Hz
- 50/60 Hz
- magnetic field

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: 2 hours/day for 3 months	magnetic flux density: 100 µT

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Exposure duration	2 hours/day for 3 months

Exposure setup

Exposure source	not specified
Sham exposure	A sham exposure was conducted.

Parameters

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

Exposed system:

Methods Endpoint/measurement parameters/methodology

endocrine changes: melatonin level in serum and whole blood samples (after activation with phytohemagglutinin, ELISA)

Investigated system:

isolated bio./chem. substance
blood, serum

Investigated organ system:

endocrine system

Time of investigation:

after exposure

Main outcome of study (acc. to author)

Exposure of rats to the magnetic field had no significant effect on melatonin levels in serum and whole blood samples compared to the control group.
However, melatonin levels in whole blood samples of both groups were about 2.5 times higher than in serum, indicating a noteworthy melatonin production in blood cells. That might challenge the historical assumption that the pineal gland is the main source of melatonin in vertebrates.
The authors conclude that exposure of rats to a 50 Hz magnetic field has no effect on the melatonin production of blood cells.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

not stated/no funding

Touitou Y et al. (2012): The effects of extremely low-frequency magnetic fields on melatonin and cortisol, two marker rhythms of the circadian system
Dyche J et al. (2012): Effects of power frequency electromagnetic fields on melatonin and sleep in the rat
Cakir DU et al. (2009): Alterations of Hematological Variations in Rats Exposed to Extremely Low Frequency Magnetic Fields (50Hz)
Kumlin T et al. (2005): Exposure to a 50-Hz Magnetic Field Induces a Circadian Rhythm in 6-hydroxymelatonin Sulfate Excretion in Mice
Bakos J et al. (2002): One week of exposure to 50 Hz, vertical magnetic field does not reduce urinary 6-sulphatoxymelatonin excretion of male wistar rats
John TM et al. (1998): 60 Hz magnetic field exposure and urinary 6-sulphatoxymelatonin levels in the rat
Loscher W et al. (1998): Exposure of female rats to a 100-microT 50 Hz magnetic field does not induce consistent changes in nocturnal levels of melatonin
Bakos J et al. (1997): Urinary 6-sulphatoxymelatonin excretion is increased in rats after 24 hours of exposure to vertical 50 Hz, 100 microT magnetic field
Bakos J et al. (1995): Sinusoidal 50 Hz, 500 microT magnetic field has no acute effect on urinary 6-sulphatoxymelatonin in Wistar rats
Selmaoui B et al. (1995): Sinusoidal 50-Hz magnetic fields depress rat pineal NAT activity and serum melatonin. Role of duration and intensity of exposure
Kato M et al. (1994): Circularly polarized 50-Hz magnetic field exposure reduces pineal gland and blood melatonin concentrations of Long-Evans rats
Kato M et al. (1994): Horizontal or vertical 50-Hz, 1-microT magnetic fields have no effect on pineal gland or plasma melatonin concentration of albino rats
Kato M et al. (1993): Effects of exposure to a circularly polarized 50-Hz magnetic field on plasma and pineal melatonin levels in rats