TY - JOUR
T1 - Dynamics of estrogen biomarker responses in rainbow trout exposed to 17β-estradiol and 17α-ethinylestradiol
AU - Thomas-Jones, Emma
AU - Thorpe, Karen
AU - Harrison, Nicola
AU - Thomas, Gethin
AU - Morris, Ceri
AU - Hutchinson, Thomas
AU - Woodhead, Stuart
AU - Tyler, Charles
PY - 2003/12
Y1 - 2003/12
N2 - We have investigated the response dynamics of the estrogen-dependent genes vitellogenin (VTG) and the vitelline envelope proteins (VEPs) as well as circulating VTG in immature female rainbow trout (Oncorhynchus mykiss) exposed to 17β-estradiol (E2) and 17α-efhinylestradiol (EE2) for periods of 7 and 14 d. Gene responses were quantified by measurement of messenger RNA (mRNA) in liver extracts using a chemiluminescent hybridization protection assay. Circulating VTG was measured by a homologous enzyme-linked immunosorbent assay. Exposure to both E2 and EE2 induced concentration-dependent increases in all biomarkers. The data presented indicate that VEP genes may be more sensitive to estrogens than the VTG gene. The biomarker lowest-observed-effect concentrations (biomarkerLOEC) in the 14-d study with E2 were 14 ng/L (VTG protein, VTG mRNA, VEPβ, and VEPγ) or 4.8 ng/L (VEPα). The EE2 was 5- to 66-fold more potent depending on the biomarker studied. In the 7-d study, all biomarkers were elevated after 48-h exposure to E2, with biomarkerLOECs of 30 ng/L (VTG protein, VTG mRNA, and VEPγ) or 9.7 ng/L (VEPα and VEPβ). Vitellogenin mRNA was induced up to 1,000-fold above baseline, and this translated into an increase of approximately 50,000-fold in circulating VTG. In conclusion, all biomarkers responded to estrogen exposure at environmentally relevant concentrations.
AB - We have investigated the response dynamics of the estrogen-dependent genes vitellogenin (VTG) and the vitelline envelope proteins (VEPs) as well as circulating VTG in immature female rainbow trout (Oncorhynchus mykiss) exposed to 17β-estradiol (E2) and 17α-efhinylestradiol (EE2) for periods of 7 and 14 d. Gene responses were quantified by measurement of messenger RNA (mRNA) in liver extracts using a chemiluminescent hybridization protection assay. Circulating VTG was measured by a homologous enzyme-linked immunosorbent assay. Exposure to both E2 and EE2 induced concentration-dependent increases in all biomarkers. The data presented indicate that VEP genes may be more sensitive to estrogens than the VTG gene. The biomarker lowest-observed-effect concentrations (biomarkerLOEC) in the 14-d study with E2 were 14 ng/L (VTG protein, VTG mRNA, VEPβ, and VEPγ) or 4.8 ng/L (VEPα). The EE2 was 5- to 66-fold more potent depending on the biomarker studied. In the 7-d study, all biomarkers were elevated after 48-h exposure to E2, with biomarkerLOECs of 30 ng/L (VTG protein, VTG mRNA, and VEPγ) or 9.7 ng/L (VEPα and VEPβ). Vitellogenin mRNA was induced up to 1,000-fold above baseline, and this translated into an increase of approximately 50,000-fold in circulating VTG. In conclusion, all biomarkers responded to estrogen exposure at environmentally relevant concentrations.
U2 - 10.1897/03-31
DO - 10.1897/03-31
M3 - Article
SN - 0730-7268
VL - 22
SP - 3001
EP - 3008
JO - Environmental Toxicology and Chemistry
JF - Environmental Toxicology and Chemistry
IS - 12
ER -