Target gene expression and morphological masculinization in mosquitofish(Gambusia affinis)exposed to 17α-methyltestosterone

The effects of 17α-methyltestosterone(MT)on target gene expression and morphological masculinization in female mosquitofish(Gambusia affinis)during the growth and development is studied in order to test if the level of ARα mRNA expression in mosquitofish can be considered a valid biomarker for aquaculture androgen POPs.With juvenile female mosquitofish exposed to MT with 0.5,5,50 and 500 nmol/L for 21 d,the body length(BL),body weight(BW),body health index(CF),and the anal fin 3rd fin section length(FL),the section number(FJ),and the most wide department width(FW),as well as the level of ARα mRNA and VTGα mRNA expression were quantitatively determined by morphology and in vitro methods,and set the control group and the parallel groups.The results showed that the BL and CF in female juvenile exposed to different concentrations of MT for 21 d were not significantly different,only the BW in fish exposed to 50 and 500 nmol/L of high-dose groups was significantly decreased(P0.05)when compared with the control group;the FJ in 3rd fin of anal fin showed a significant increase,FL was along with extending and FW also showed a significant increase in width(P0.05);Female juveniles were exposed to different concentrations of MT after 21 d,ARα mRNA expression level was displayed dose-related increase significantly(P0.05).The results indicated that the androgenic effects of MT was very significant,resulting in the morphological masculinization in female mosquitofish during the growth and development process;ARα mRNA expression levels could be used as the ideal biomarkers for monitoring the aquaculture water androgen pollutants.