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.

By: Abhold RH, Ortner MJ, Galvin MJ, McRee DI

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

endocrine changes: thyroid and adrenal axes hormones

Exposure

- microwaves

Exposure	Parameters
Exposure 1: 2.45 GHz Modulation type: CW Exposure duration: continuous for 8 h	power density: 100 mW/cm² spatial average power density: 2 mW/cm² spatial average SAR: 0.22 mW/g

Exposure 1

Main characteristics

Frequency	2.45 GHz
Type	electromagnetic field
Exposure duration	continuous for 8 h

Modulation

Modulation type	CW

Exposure setup

Exposure source	horn antenna
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:

animal
rat/Charles River
whole body

Methods Endpoint/measurement parameters/methodology

endocrine changes: T₄ and T₃ serum concentration and T₃ uptake via radioimmunoassay; corticosterone serum concentration (competetive protein binding method)

Investigated system:

isolated bio./chem. substance

Investigated organ system:

endocrine 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:

medical/biological study
experimental study
full/main study

Study funded by

not stated/no funding

Jin YB et al. (2013): Effects of simultaneous combined exposure to CDMA and WCDMA electromagnetic fields on serum hormone levels in rats
Misa Agustino MJ et al. (2012): Electromagnetic fields at 2.45 GHz trigger changes in heat shock proteins 90 and 70 without altering apoptotic activity in rat thyroid gland
Esmekaya MA et al. (2010): Pulse modulated 900 MHz radiation induces hypothyroidism and apoptosis in thyroid cells: A light, electron microscopy and immunohistochemical study
Augner C et al. (2010): Effects of Exposure to GSM Mobile Phone Base Station Signals on Salivary Cortisol, Alpha-Amylase, and Immunoglobulin A
Sinha RK (2008): Chronic non-thermal exposure of modulated 2450 MHz microwave radiation alters thyroid hormones and behavior of male rats