Event Title
Determination of the Liver and Fill Pathogenesis of 12alphaethynylestradiol as a Function of Nitrite Concentration and Reversal by Tamoxifen in the Rainbow Darter
Location
Ostrander
Start Date
12-4-2004 1:45 PM
End Date
12-4-2004 3:15 PM
Student's Major
Biological Sciences
Student's College
Science, Engineering and Technology
Mentor's Name
Steve Mercurio
Mentor's Department
Biological Sciences
Mentor's College
Science, Engineering and Technology
Description
Rainbow darters were studied since they are a sexually dimorphic Minnesota fish species that are intolerant of water pollution (possibly including endocrine disrupters). They were exposed to ethynylestradiol (synthetic estrogen used in medications) at concentrations which are likely found in sewage from cities with regional medical centers such as Rochester and Mankato to see how disrupting their hormonal environment affects their response to other prevalent pollutants in the water. For example, high concentrations of nitrates and nitrites in water, originating from human or animal wastes, are known to cause gill and liver damage in fish. Additionally, the overproduction of a female ovarian protein (vitellogenin) by the liver of estrogen-treated fish is known to affect the nitrogen balance of various species of animals. Female and male darters were exposed to nothing (control), 0.002% ethanol (solvent control) or 200 ng/L 17a-ethynylestradiol (estrogen effect) for 21 days.' Tamoxifen, an inhibitor of the estrogen receptor, was put into tanks containing estradiol at concentrations of 2-20,000 ng/L to attempt to reverse any estrogenic effect. Nitrite concentrations in the tanks increased with estrogen in either sex, but tamoxifen only reversed this increase in female fish in a concentration-dependent manner. Tissue sections stained for the presence of protein will be presented showing all alterations in the liver and gill function due to estrogen and increasing nitrite concentrations and those reversed by tamoxifen. These results are significant because no one has linked increased sensitivity of fish to nitrates from fertilizer runoff or human waste in sewage to endocrine disruption by estrogen in fish.
Determination of the Liver and Fill Pathogenesis of 12alphaethynylestradiol as a Function of Nitrite Concentration and Reversal by Tamoxifen in the Rainbow Darter
Ostrander
Rainbow darters were studied since they are a sexually dimorphic Minnesota fish species that are intolerant of water pollution (possibly including endocrine disrupters). They were exposed to ethynylestradiol (synthetic estrogen used in medications) at concentrations which are likely found in sewage from cities with regional medical centers such as Rochester and Mankato to see how disrupting their hormonal environment affects their response to other prevalent pollutants in the water. For example, high concentrations of nitrates and nitrites in water, originating from human or animal wastes, are known to cause gill and liver damage in fish. Additionally, the overproduction of a female ovarian protein (vitellogenin) by the liver of estrogen-treated fish is known to affect the nitrogen balance of various species of animals. Female and male darters were exposed to nothing (control), 0.002% ethanol (solvent control) or 200 ng/L 17a-ethynylestradiol (estrogen effect) for 21 days.' Tamoxifen, an inhibitor of the estrogen receptor, was put into tanks containing estradiol at concentrations of 2-20,000 ng/L to attempt to reverse any estrogenic effect. Nitrite concentrations in the tanks increased with estrogen in either sex, but tamoxifen only reversed this increase in female fish in a concentration-dependent manner. Tissue sections stained for the presence of protein will be presented showing all alterations in the liver and gill function due to estrogen and increasing nitrite concentrations and those reversed by tamoxifen. These results are significant because no one has linked increased sensitivity of fish to nitrates from fertilizer runoff or human waste in sewage to endocrine disruption by estrogen in fish.
