Extremely low-frequency electromagnetic fields differentially regulate estrogen receptor-α and -β expression in the rat olfactory bulb

Recently, the effects of extremely low-frequency electromagnetic fields (ELF EMF) on biological systems have been extensively investigated. In this report, the influence of ELF EMF on olfactory bulb (OB) estrogen receptor-α (ERα) mRNA and -β (ERβ) mRNA expression was studied by RT-PCR in adult female and male rats. Results reveal for the first time that ELF EMF exerted a biphasic effect on female OB ERβ mRNA gene expression, which increased during diestrous and decreased during estrous. We did not observe any influence of ELF EMF on female OB ERα mRNA expression. Our data demonstrate a fluctuating pattern of ER-α and -β mRNA expression in the female OB throughout the phases of the estrous cycle in non-ELF EMF-exposed animals. Thus the highest ERα expression was observed in diestrous and the lowest in proestrous. The pattern of ERβ mRNA was less variable, the lowest expression was observed in diestrous. ER-α mRNA and -β mRNA expression level in the male OB did not exhibit any variation either in ELF EMF-exposed or non-ELF EMF-exposed animals. In summary, ELF EMF modulate ERβ gene expression in the OB of female adult rats but not in males.