• experimental
  
• epidemiological
  

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Medical/biological Study (experimental study)

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

PubMed Entry

Journal web site

Aim of study (according 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

• endocrine changes: content of TSH and thyroid hormones

Exposure

Field characteristics	Parameters
900 MHz continuous wave (CW) exposure duration: repeated daily exposure, 30 min/day, 5 days/week for 4 weeks	power flux density: 1 mW/cm² mean value (± 0.4 mW/cm²) SAR: 2 W/kg peak value

Exposed system:
animal (species/strain): rat/Sprague-Dawley
whole body exposure

Methods
Endpoint/Measurement parameters/Methodology

• endocrine changes: concentration of TSH (immunoradiometric assay, IRMA), T₃ andT₄ hormone (radioimmunoassay)

Main outcome of study (according 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: medical/biological study, experimental study, full/main study)

Study funded by

• not stated

• Djeridane Y et al. (2008): Influence of electromagnetic fields emitted by GSM-900 cellular telephones on...
• Mann K et al. (1998): Effects of pulsed high-frequency electromagnetic fields on the neuroendocrine...