Exposure to the environmental estrogen bisphenol A differentially modulated estrogen receptor-α and -β immunoreactivity and mRNA in male mouse testis

We examined the effects of bisphenol A (0.5 mug/ml or 50 mug/ml) in the drinking water on estrogen receptor (ER) alpha and beta proteins and mRNA in the testis of young mice following 8-weeks of oral administration of bisphenol A utilizing inummohistochemistry and semiquantitative reverse transcription polymerase chain reaction amplification (RT-PCR). ERbeta was clearly localized in the nuclei of spermatogonia and/or spermatocytes. ERbeta immunopositive cell numbers per testis section were significantly decreased in the 50 mug/ml bisphenol A-treated group compared with control and the 0.5 mug/ml bisphenol A-treated group. The number of ERalpha positive cells in the testis was significantly lower than ERalpha positive cells in control group. ERalpha immunopositive cell numbers per testis section were markedly increased in the 50 mug/ml bisphenol A-treated group compared with the control and the 0.5 mug/ml bisphenol A-treated group. ER mRNA expression was significantly decreased in the 50 mug/ml bisphenol A-treated group compared with the control and the 0.5 mug/ml bisphenol A-treated group. In contrast, ERalpha mRNA expression was markedly increased in the 50 mug/ml bisphenol A-treated group compared with the control and the 0.5 mug/ml bisphenol A-treated group. The existence of ERalpha and beta in the testis suggests that estrogens directly affect germ cells during testicular development and spermatogenesis, and differential modulation of ERalpha and beta in the testis could be involved in the effects of bisphenol A. (C) 2002 Elsevier Science Inc. All rights reserved.