Gene expression in primary cultures of male medaka (Oryzias latipes) hepatocytes induced by 17β-estradiol with quantitative real-time RT-PCR

A method of applying quantitative real-time RT-PCR to cultures of male medaka hepatocytes was developed to evaluate estrogenic activity. Primary cultures of male medaka (Oryzias latipes) hepatocytes were exposed to 17β-estradiol (E2) at 100 nmol·L-1 for 2, 4, 6, 8-day exposure, and 1, 10, 100, 1000 and 10000 nmol·L-1 E2 for 4 days. The VTG-I, VTG-Ⅱ, CHG-H, CHG-L and ERα gene expressions were determined using quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR). It was found that dose-dependent VTG-I, VTG-Ⅱ, CHG-H, CHG-L and ERα gene expressions in hepatocytes were induced, and obvious expressions were observed even at 1 nmol·L-1 of E2. This method is more sensitive compared with other in vitro methods for evaluating estrogenic activity. Thus, applying quantitative real-time RT-PCR to primary cultures of male medaka hepatocytes has potential application in the evaluation of estrogenic activity of endocrine disrupting chemicals or environmental samples.