Effect of estradiol and nonylphenol on mRNA levels of vitellogenin II in the liver of chicken embryos

摘要

Nonylphenol is one of the endocrine disrupting agents with estrogenic activity in some vertebrates. The present study was conducted to assess estrogenic activity of p-nonylphenol (NP) in chicken embryos by determining mRNA levels of liver vitellogenin II (VTG II). Fertile chicken eggs were incubated at 37.5 deg C using standard conditions. In the group 1, the eggs were treated with a single injection of either NP at doses of 50, 10, 1, 0.5, 0.2, 0.1, 0.01 and 0.001 mg/egg or estradiol-17 beta (E2)at doses of 1.0, 0.1 and 0.01 mg/egg in 50 mu l on day 16 of incubation. In the group 2, the eggs were treated with double injections of either NP or E2 on days 13 and 16 of incubation. In the control group the eggs were treated with the vehicle (propanediol (PD), 50 mu l/egg). On day 18 of incubation the liver was collected and total RNA was extracted. VTG II mRNA levels were determined by reverse transcription-polymerase chain reaction (RT-PCR) assay. All the embryos were alive in the group of E2, PDor 0.01 and 0.001 mg/egg of NP. Only 17 percent (3/18) of embryos were alive in the group of NP at 10 mg/egg. No VTG II mRNA was detected in the control group, whereas distinct VTG II mRNA was revealed in the E2 treatment group where there was higher expression in the group 2 than in the group 1. Weak but distinct VTG II mRNA was detected in the NP treatment group. This study indicates that NP may have estrogenic activity in terms of liver VTG II mRNA assessed by RT-PCR assay in the chicken embryo.