Study type: Medical/biological study (experimental study)

Morphophysiological status of rat thyroid gland after subchronic exposure to low frequency electromagnetic field med./bio.

Published in: Med Pregl 2001; 54 (3-4): 119-127

Aim of study (acc. to author)

The effects of exposure of rats to a magnetic and electric field (50 Hz) on the histology of the thyroid gland and thyroid hormone concentrations in the blood should be investigated.

Background/further details

The rats were divided into two groups: 1) exposure (n=12) and 2) sham exposure (n=11). Exposure started 24 hours after birth of rats.



Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 7 h/day, 5 days/week, for 3 months

Exposure 1

Main characteristics
Frequency 50 Hz
Exposure duration continuous for 7 h/day, 5 days/week, for 3 months
Exposure setup
Exposure source
Setup single coil of 2.5 mm thick wire placed on a wooden frame with 1320 turns; cages with animals were placed symmetrically on both sides of the coil
Sham exposure A sham exposure was conducted.
Measurand Value Type Method Mass Remarks
electric field strength 10 V/m - - - -
magnetic flux density 500 µT maximum - - at the cage's side near the coil
magnetic flux density 50 µT minimum - - at the cage's side opposite to the coil

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

In histological analyses, the exposure group showed significant changes compared to the sham exposure group: increased volume density of thyroid follicles, decreased thickness of the follicular epithelium and intrafollicular colloid content, increased volume density of parafollicular cells, decreased volume of interfollicular connective tissue and increased number of degranulated mast cells.
No significant differences were observed in the concentrations of triiodothyronine and thyroxine concentrations in the blood between exposed animals an the sham exposure group, although a tendency towards smaller values in exposed animals was observed.
The authors conclude that exposure of rats to a magnetic and electric field (50 Hz) might cause alterations in the histology and function of the thyroid gland, which could be interpreted as a decrease of thyroid gland activity.

Study character:

Study funded by

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