Effects of 17β-Estradiol on Estrogen Receptor α and β mRNA Expression in Tissues of the Olive Flounder (Paralichthys olivaceus)

Abstract

This study examined the effects of an injection of 17beta-estradiol (E2) on the expression of estrogen receptor (ER) alpha and beta subtypes in the olive flounder (Paralichthys olivaceus). Time- and dose-related effects of E2 on ERalpha and ERbeta mRNA expression were determined by RT-PCR. In the liver of males, the two ER transcripts were up-regulated at 24 h. In the liver of females, ERalpha and ERbeta were upregulated at 36 h with the highest dose. After E2 treatment, increases in ERalpha and ERbeta expression were observed in the testis and ovary at 36 h; RT-PCR analysis showed that this increase was dose-dependent. After E2 treatment, the brain tissue of males showed lower levels of ERalpha and ERbeta compared with the untreated control group, whereas the brain tissue of females showed no significant difference compared with controls. The results confirm the hypothesis that ER regulation is tissue-specific and may be involved in E2-mediated regulation of reproduction in the olive flounder.