An emerging water contaminant, semicarbazide, exerts an anti-estrogenic effect in zebrafish (Danio rerio)

To determine the endocrine disrupting effect of semicarbazide, an emerging water contaminant, the changes in transcript levels of hepatic estrogen-response genes including vitellogenin-1 (vtg-1), estrogen receptor α (ERα), and estrogen receptor β (ERβ) were measured in male and female zebrafish exposed to semicarbazide with or without exogenous 17β-estradiol (E2). Exposure of male zebrafish to semicarbazide for 96 h or 28 days resulted in no significant induction in hepatic vtg-1, ERα, or ERβ mRNA expression, indicating that semicarbazide has no estrogenic effect. However, a remarkable anti-estrogenic effect of semicarbazide was demonstrated: semicarbazide treatment of female zebrafish for 96 h and 28 days resulted in significant decreases in transcript levels of vtg-1, ERα, and ERβ, as well as decreases in the gonadosomatic index level after 28 days. Moreover, semicarbazide exposure significantly inhibited the induction of vtg-1, ERα and ERβ mRNA by E2 when male zebrafish were co-exposed for 28 days.