Author
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Shappell, Nancy |
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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 6/29/2015 Publication Date: 11/1/2015 Citation: Shappell, N.W. 2015. Estrogenic compounds, chemical quantitation, biological assessment – What we know, what we don’t, and what should our future priorities be? [abstract]. 36th Annual Society of Environmental and Toxicology and Chemistry. Nov. 1-5, 2015. Salt Lake City, UT. Paper no. WP110. Interpretive Summary: Over the last two decades, the literature has become replete with reports quantifying estrogenic chemicals in the environment ranging from natural hormones to plasticizers. In addition to measuring concentrations, laboratories have developed various in vitro assays to assess estrogenic activity of chemicals, as well as environmental samples. Information pertaining to the in vivo effects of the chemicals is much less exhaustive and their relationship to in vitro results is often ignored. Ranking of chemicals can vary significantly depending on the source of transfected estrogen receptor . One lab reported trout versus human receptors were 62 fold more sensitive when exposed to one compound, but in contrast, trout receptors showed only 0.04% of the response human receptors elicited to another chemical. The same lab reported in vivo response to one chemical was 10,000 less estrogenic than estradiol, but by in vitro assay using transfected estradiol receptors from fish, the compound was only 600 less estrogenic than estradiol. Chemical additivity has been reported from both in vitro and in vivo laboratory exposures, though similar additivity has not been reported for humans “dosed” with multiple estrogenic chemicals. While agriculture and wastewater treatment plants have been implicated as point source contributors of estrogenic contaminants in surface waters, studies of many water bodies have failed to detect these contaminants at biologically relevant concentrations. The consequences of various estrogenic agricultural inputs need to be assessed in the context of the specific areas of release. Release of these compounds into surface waters in arid regions could result in significant environmental impacts, while posing no problem in less arid regions. Finally, some recent reports have quantified estrogen concentration as a sum of all estrogens (ignoring relative estrogenic potential of the specific estrogen). The relevance of these findings will be discussed and suggestions for future research directions made. Technical Abstract: Over the last two decades, the literature has become replete with reports quantifying estrogenic chemicals in the environment ranging from natural hormones to plasticizers. In addition to measuring concentrations, laboratories have developed various in vitro assays to assess estrogenic activity of chemicals, as well as environmental samples. Information pertaining to the in vivo effects of the chemicals is much less exhaustive and their relationship to in vitro results is often ignored. Ranking of chemicals can vary significantly depending on the source of transfected estrogen receptor . One lab reported trout versus human receptors were 62 fold more sensitive when exposed to one compound, but in contrast, trout receptors showed only 0.04% of the response human receptors elicited to another chemical. The same lab reported in vivo response to one chemical was 10,000 less estrogenic than estradiol, but by in vitro assay using transfected estradiol receptors from fish, the compound was only 600 less estrogenic than estradiol. Chemical additivity has been reported from both in vitro and in vivo laboratory exposures, though similar additivity has not been reported for humans “dosed” with multiple estrogenic chemicals. While agriculture and wastewater treatment plants have been implicated as point source contributors of estrogenic contaminants in surface waters, studies of many water bodies have failed to detect these contaminants at biologically relevant concentrations. The consequences of various estrogenic agricultural inputs need to be assessed in the context of the specific areas of release. Release of these compounds into surface waters in arid regions could result in significant environmental impacts, while posing no problem in less arid regions. Finally, some recent reports have quantified estrogen concentration as a sum of all estrogens (ignoring relative estrogenic potential of the specific estrogen). The relevance of these findings will be discussed and suggestions for future research directions made. |
