Comparison of vitellogenin responses protein and gene expression of to 4-Nonylphenol in Rockfish (Sebastes schlegeli )

Abstract

To investigate the in vivo estrogenic activity of 4-Nonylphenol (4-NP) on reproductive function, we have measured the expression level of rockfish vitellogenin (rVTG) mRNA, concentration of plasma VTG and levels of plasma estradiol-17b (E2) and testosterone (T) by radioimmunoassay (RIA). The level of rVTG mRNA expression was increased at 48 h after injection with 4-NP of 10 mg/kg b.w. and after injection in both male and female rockfish. The level of rVTG mRNA expression was increased at 24 h after injection in male rockfish injected with 4-NP of 25 mg/kg b.w., whereas the level of rVTG mRNA expression was increased at 12 h after injection in female injected with same dosage. Concentrations of plasma rVTG in female and male injected with 4 -NP of 10 mg/kg b.w. and 25 mg/kg b.w. were increased at 72 h after injection. Plasma concentrations of T and E2 in female and male injected with 4-NP were not significantly different between two dosages of 10 mg/kg b.w. and 25 mg/kg b.w. These results suggest that 4-NP may disrupt the reproductive system of immature rockfish by acting directly on vitellogenesis. Immature females injected with 4-NP were more sensitive than immature males.