Study type: Medical/biological study (experimental study)

Studies on acute in vivo exposure of rats to 2450-MHz microwave radiation. II. Effects on thyroid and adrenal axes hormones. med./bio.

Published in: Radiat Res 1981; 88 (3): 448-455

Aim of study (acc. to author and editor)

To study the endocrine effects of microwave exposure of rats.

Background/further details

Rats were exposed in vivo, and possible endocrine changes were investigated by determination of several endocrine hormones in blood samples. Investigations were carried out concerning the hormones thyroxine (T4), triiodothyronine (T3), and corticosterone. T4 and T3 are formed and secreted by the thyroid gland, whereas corticosterone is a adrenal cortex product.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2.45 GHz
Modulation type: CW
Exposure duration: continuous for 8 h

Exposure 1

Main characteristics
Frequency 2.45 GHz
Type
Exposure duration continuous for 8 h
Modulation
Modulation type CW
Exposure setup
Exposure source
Distance between exposed object and exposure source 1.55 m
Chamber chamber 2,5 m x 3,0 m x 2,5 m lined with HPY-18 microwave absorber( -45dB)
Setup animals placed in 2.5 cm thick Styrofoam cages (10 cm x 20 cm) positioned inside the chamber
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power density 100 mW/cm² spatial average measured - -
power density 2 mW/cm² spatial average measured - -
SAR 0.22 mW/g - - whole body -

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The microwave exposure had no effects on the serum concentrations of thyroxine (T4), triiodothyronine (T3) and the uptake of T3. These unaltered hormone concentrations could be interpreted in that way that the thyroid gland was not affected by exposure. The serum concentrations of corticosterone, which is adrenal cortex made, were nonuniform. Low level exposure leads to increased concentration, whereas at high level exposure the corticosterone concentration was similar to the unexposed controles.
These results suggest that the experimental procedure effects the adrenal cortex, and that this effect could be counteracted by high level exposure.

Study character:

Study funded by

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