Medical/biological study (experimental study)

Study on pineal function and DMBA-induced breast cancer formation in rats during exposure to a 100-mG, 50 Hz magnetic field med./bio.

By: Mevissen M, Lerchl A, Loscher W

Published in: J Toxicol Environ Health 1996; 48 (2): 169-185

Journal partially peer-reviewed/peer-review process unclear

A total of 216 rats were used in this study, divided into four groups: Group A) 99 animals, DMBA treated, MF exposed. Group B) 99 animals, DMBA treated, MF sham-exposed. Group C) 9 animals, non-DMBA-treated, MF exposed. D) 9 animals, non-DMBA-treated, MF-sham-exposed.
The first DMBA (5 mg/rat) application occured prior exposure and was followed by three more applications in a weekly interval up to a total doses of 20 mg/rat.

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: 24 h/day, 7 days/week for 91 days	electric field strength: 29 V/m minimum (unspecified) electric field strength: 69 V/m maximum (unspecified) magnetic flux density: 10 µT effective value

Exposure source	Merritt coils
Setup	4 Merritt coils, 26 and 11 turns on outer and inner coils, copper wire gauge 1.5 m²
Sham exposure	A sham exposure was conducted.

Measurand	Value	Type	Method	Mass	Remarks
electric field strength	29 V/m	minimum	measured	unspecified	-
electric field strength	69 V/m	maximum	measured	unspecified	-
magnetic flux density	10 µT	effective value	measured	-	-

Exposed system:

Investigated system:

Investigated organ system:

Time of investigation:

A non statistically significant tendency to an enhanced tumor incidence in MF-exposed rats could be observed. Tumor size was similar in MF-exposed and sham-exposed groups. DMBA-treated animals had a significantly lower nocturnal pineal melatonin level as compared with non-DMBA-treated animals. Also MF-exposed animals had significantly lower nocturnal melatonin serum levels as compared with sham exposed animals. The data demonstrate that significantly decreased melatonin levels, caused by MF exposure, are not associated with a significant effect on the development and growth of DMBA-induced mammary tumors.

Study character:

Berufsgenossenschaft der Feinmechanik und Elektrotechnik (BGFE), Germany
Forschungsverbund Elektromagnetische Verträglichkeit Biologischer Systeme (Research Association of Electromagnetic Compatibility of Biological Systems), Technical University Braunschweig, Germany

Dyche J et al. (2012): Effects of power frequency electromagnetic fields on melatonin and sleep in the rat
Negishi T et al. (2008): Lack of promotion effects of 50 Hz magnetic fields on 7,12-dimethylbenz(a)anthracene-induced malignant lymphoma/lymphatic leukemia in mice
McCormick DL et al. (1999): Chronic toxicity/oncogenicity evaluation of 60 Hz (power frequency) magnetic fields in B6C3F1 mice
Boorman GA et al. (1999): Chronic toxicity/oncogenicity evaluation of 60 Hz (power frequency) magnetic fields in F344/N rats
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
Mevissen M et al. (1996): Exposure of DMBA-treated female rats in a 50-Hz, 50 microTesla magnetic field: effects on mammary tumor growth, melatonin levels, and T lymphocyte activation