Sensitivities of mRNA expression of vitellogenin, choriogenin and estrogen receptor by estrogenic chemicals in medaka, Oryzias latipes

Abstract

Gene expression levels of choriogenin, vitellogenin, and estrogen receptor were determined using a reverse transcription-polymerase chain reaction (RT-PCR) technique after exposure to estrogenic chemicals to compare the sensitivities of the biomarkers of endocrine disruption in medaka, Oryzias latipes. Mature male medaka were treated with a single dose of 100 μ/1 of 17α-ethinylestradiol, nonylphenol, and bisphenol A for 6 days, then RNA was extracted from the livers of treated fish for RT-PCR. Primers of RT-PCR for choriogenin H and L, and estrogen receptor were synthesized based on previously known cDNA sequences, and primers for vitellogenin I and II were synthesized based on the partial cDNA which was sequenced in this study. When the five biomarker genes were amplified by RT-PCR under the same condition, the mRNA induction level of each gene was elevated with different sensitivities. Conclusively, choriogenin L, which is a precursor of zona radiata protein (ZI-3) with molecular weight of 49 kD, showed the most sensitive gene expression in all the treated groups.