Study type: Medical/biological study (experimental study)

Effects of 900MHz electromagnetic field on TSH and thyroid hormones in rats. med./bio.

Published in: Toxicol Lett 2005; 157 (3): 257-262

Aim of study (acc. to author)

To study whether the serum TSH (thyroid stimulating hormone) and T3 (triiodothronine)-T4 (thyroxine) hormone levels of adult male rats could be altered after exposure to 900 MHz GSM-like electromagnetic field generator.

Background/further details

Thyroid activity is regulated by the thyroid stimulating hormone (TSH) (secreted by pituitary). Elevated TSH levels induce the thyroid to elaborate triiodothronine (T3) and thyroxine (T4).
Animals were maintained under a 12 h light/12 h dark cycle and grouped as follows: control group (without stress and electromagnetic field), sham-exposed group and a 900 MHz group.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: CW
Exposure duration: repeated daily exposure, 30 min/day, 5 days/week for 4 weeks

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Exposure duration repeated daily exposure, 30 min/day, 5 days/week for 4 weeks
Modulation
Modulation type CW
Exposure setup
Exposure source
Chamber A special exposure device with five exposure antennas was used. One exposure system consisted of a ventilated round plastic tube cage (12 cm long x 5.5 cm in diameter) and a half-wave dipole antenna.
Setup The whole body of the rat was positioned in close contact above the antenna.
Additional info Rats were allocated to three groups: exposed to EMF, sham-exposed, and control (without stress and EMF).
Parameters
Measurand Value Type Method Mass Remarks
power density 1 mW/cm² mean measured - ± 0.4 mW/cm²
SAR 2 W/kg peak value - - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

TSH values and T3-T4 at the 900MHz exposure group were significantly lower than the sham-exposed group. There were no statistically significant differences in serum TSH values and T3-T4 hormone contents between the control and the sham-exposed group.
These data indicate that 900MHz electromagnetic field emitted by cellular phones decrease serum TSH and T3-T4 levels. This result may be possibly the result of tissue heating. Further investigations are needed in order to clearly show that the degree of TSH and thyroid hormones suppression by radiofrequency electromagnetic field.

Study character:

Study funded by

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