RESUMO
The effect of electromagnetic field [EMF] on serum thyroid stimulating hormone [TSH] and triiodothyronine-thyroxin [T3-T4] hormones levels of adult male Sprague-Dawley rats were studied. Fifty rats were used in three independent groups, 20 of which were control [without stress and EMF], 20 of which were exposed to 900 MHz EMF and 10 of which were sham-exposed. The exposures were performed 30 min/day, for 5 days/week for 4 weeks to 900 MHz EMF. Sham-exposed animals were kept under the same environmental conditions as the study groups except with no EMF exposure. The concentration of TSH and T3-T4 hormones in the rat serum was measured by using an enzyme liked immunsorbent assay [ELISA] method for TS, T3, and T4 hormones. TSH values and T3-T4 at the 900 MHz EMF group were significantly lower than the sham-exposed group [p<0.01]. There were no statistically significant differences in serum TSH values and T3-T4 hormones concentrations between the control and the sham-exposed group [p>0.05]. These results indicate that 900 MHz EMF emitted by cellular telephones decrease serum TSH and T3-T4 levels