Short-term exposure to a 1439-MHz TDMA signal exerts no estrogenic effect in rats

The aim of this study was to elucidate the possible effects of short-term exposure to a 1439-MHz electromagnetic field (EMF) employing time division multiple access (TDMA), which is the basis of the Japanese Personal Digital Cellular system, on estrogenic activity in rats. Sixty-four ovariectomized female Sprague-Dawley rats were divided into four groups: EMF exposure (EM), sham exposure, cage control, and 17 beta-estradiol injected (E2). The EM group was exposed, for 4 h per day on three consecutive days, to the 1439-MHz TDMA signal that produced 5.5-6.1 and 0.88-0.99 W/kg average specific absorption rates in the brain and the whole body, respectively. The uterine wet mass and serum estradiol level significantly increased in the E2 group, while there were no differences among the other three groups. Although negative effects of long-term EMF exposure must be thoroughly investigated before a final conclusion can be reached, our results do not support the assumption that the high frequency EMF used in cellular phones exerts estrogenic activity.