Estrogen-like Effects in Male Goldfish Co-exposed to Fluoxetine and 17 Alpha-Ethinylestradiol

The antidepressant fluoxetine (FLX) and the synthetic estrogen, 17 alpha-ethinylestradiol (EE2), are present in municipal sewage discharges. To better understand possible interactions between them, male goldfish were exposed to an ethanol control or to nominal concentrations of FLX (0.54 mu g/L) and EE2 (5 ng/L) alone and in combination for 14 days. Real-time reverse-transcription polymerase chain reaction was used to assess effects on hepatic gene expression and liquid chromatography tandem mass spectrometry to analyze the plasma proteome. The results showed an increase in estrogen receptor alpha (esr1) and vitellogenin (vtg) gene expression by 1.9-2.4-fold in the FLX and EE2 groups, but this did not reach statistical significance. In contrast, co-exposure up regulated esr1 and vtg gene expression by 5.5- and 5.3-fold, respectively. Fluoxetine and EE2 alone did not affect estrogen receptor beta (esr2), but the co-exposure down regulated esr2 expression by 50%. There was a significant increase in the number of plasma proteins that were related to endocrine system disorders in the FLX and FLX plus EE2 groups. The level of VTG protein was increased in the plasma from goldfish exposed to EE2, FLX, and FLX plus EE2. Our study demonstrates that low concentrations of FLX and EE2 in a simple mixture produce strong estrogen-like effects in the male goldfish.