Effect of Endocrine Disrupters on mRNA Expression of Vitellogenin (VTG) II and Very Low Density Lipoprotein (apo VLDL) II in the Liver of Quail Embryos

Abstract

The present study was conducted to assess estrogenic activity of nonylphenol (NP) and octylphenol (OP) in quail embryos by determining mRNA levels of liver vitellogenin (VTG) II and very low density lipoprotein (apoVLDL) II. The fertile eggs were treated with a single injection of either NP, OP or ethynyl estradiol (EE) at doses of 10 and 100 nmole/egg in 20μl on day 13 of incubation. In the control group the eggs were treated with the vehicle (corn oil, 20μl/egg). On day 15 of incubation the liver was collected and total RNA was extracted. Both mRNA levels were determined by RT-PCR assay and were expressed in relation to ø actin mRNA levels. No expression of VTG II mRNA was detected in the control group, whereas a marked induction of VTG II mRNA was revealed in the EE treatment. A weak but distinct expression of VTG II mRNA was evident in the NP and OP treatment groups. ApoVLDLII transcripts were detected in the control group and induced markedly by the injection of EE with higher expression in females. NP also induced considerable expression in females, whereas no transcripts were detected in males. OP also induced the transcript in females but in males OP at 10 nmole was effective. This study indicates that NP and OP possess estrogenic activity in terms of liver VTG II and apoVLDLII mRNA expression in the quail embryo, and that apoVLDLII expression in female embryo is more sensitive to estrogenic substances. © 2003, Japan Poultry Science Association. All rights reserved.