Induction of Chemical Biomarkers in Fish

摘要

The primary focus of this research was to develop bio-markers for the detectionof estrogenic chemicals in aquatic environments. Vitellogenin (Vg) and its corresponding mRNA have been shown to be induced by estrogenic chemicals in aquatic species. In this investigation, the probe, pSG5Vg1.1. was produced for detection of Vg expression in trout. Using northern blotting techniques, pSG5Vg1.1 was able to detect increases in liver Vg mRNA in fish treated with estradiol, a known inducer of Vg in fish. Nonylphenol (NP) and DDE, which are also thought to be estrogenic were also shown to induce trout liver Vg mRNA as detected by pSG5Vg1.1. In order to investigate the potency of NP with respect to lethality and estrogenicity, in vivo concentration-response relationships for both death and Vg mRNA induction were investigated in trout. Trout were exposed to various concentrations of NP after which the estrogenic effects were determined by RT-PCR responses of liver Vg mRNA. Estrogenic effects, as evidenced by the appearance of Vg mRNA, could be seen at as low as 10 ppb of NP. This research illustrates the utility of RT-PCR and DNA probes in detecting low levels of Vg mRNA induced by NP and possibly other estrogenic chemicals. These observations indicate that the potency of NP for its estrogenic effect is much greater than its lethal effect and that NP is apt to be estrogenic in the environment at concentrations which are not lethal.