Study type: Medical/biological study (experimental study)

Effects of weak alternating magnetic fields on nocturnal melatonin production and mammary carcinogenesis in rats med./bio.

Published in: Oncology (Williston Park) 1994; 51 (3): 288-295

Aim of study (acc. to author)

To investigate the effects of an inhomogeneous (0.3-1 µT), alternating magnetic field on tumor development and melatonin levels in DMBA treated rats.

Background/further details

A total of 72 animals were used in this study (divided into two groups/36 animals each). One group was MF-exposed, the other one served as sham-exposed control. Each animal obtained an initial oral administration of 5 mg DMBA prior the onset of exposure/sham-exposure. DMBA administration was repeated weekly up to a total dose of 20 mg.



Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: 24 h/day, 7 days/week, for 91 days

General information

Rats were assigned to two groups, a sham exposue group (n= 36) and a magnetic field exposure group (n= 36).

Exposure 1

Main characteristics
Frequency 50 Hz
Exposure duration 24 h/day, 7 days/week, for 91 days
Exposure setup
Exposure source
Setup Rats recieved administration of 5 mg DMBA (dimethylbenz(a)anthracene) per week (for 4 weeks up to a total of 20 mg) and were housed in Plexiglass cages surrounded by the coils.
Sham exposure A sham exposure was conducted.
Measurand Value Type Method Mass Remarks
magnetic flux density 300 nT minimum measured - -
magnetic flux density 1 µT maximum measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

No significant differences between groups were found in general behavior, body weight, or weight of spleen and liver. Also histopathological examination of tumors did not reveal any significant differences between the MF-exposed and the sham-exposed group. However, nocturnal melatonin serum levels were significantly reduced in the MF-exposed group.

Study character:

Study funded by

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