Non-monotonic dose-response effect of bisphenol A on rare minnow Gobiocypris rarus ovarian development.

Bisphenol A (BPA) is widely spread in the environment, and can cause various reproductive disrupting effects on different organisms, including fish. Our previous published study showed that BPA has non-monotonic (inverted U-shaped) dose-response effect on rare minnow Gobiocypris rarus ovarian weight at different concentrations. To investigate the potential mechanism, we exposed female rare minnow to 1, 15 and 225 µg L(-1) BPA for 7 days in the present study. The levels of vitellogenin (Vtg), sex hormones, hydrogen peroxide (H2O2), glutathione (GSH) and triglyceride (TG) were measured. RNA-seq of ovary tissues was also performed. Result showed that Vtg, sex hormone and TG levels showed an inverted U-shaped increased response, while H2O2 and GSH levels showed a U-shaped inhibited response. RNA-seq data showed that many genes involved in lipid metabolism, oxidative stress, and proteolysis processes were altered. The change of Vtg, H2O2, GSH and TG levels was possibly related to the altered sex hormone levels. Sex hormone's direct effect, Vtg accumulation, TG accumulation and oxidative stress induced proteolysis may contribute to the change of ovary weight.