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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Animal Metabolism-Agricultural Chemicals Research » Research » Publications at this Location » Publication #309992
Title: Modulation of estrogenic effects by environmental temperature and food availability

Author
item FEIFAREK, DAVID - St Cloud State University
item Shappell, Nancy
item SCHOENFUSS, HEIKO - St Cloud State University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/14/2014
Publication Date: 3/24/2014
Citation: Feifarek, D.J., Shappell, N.W., Schoenfuss, H.L. 2014. Modulation of estrogenic effects by environmental temperature and food availability [abstract]. Midwest Regional Society of Environmental Toxicology and Chemistry, March 24-25, 2014, Chicago, IL. p. 13.

Interpretive Summary: Endocrine-disrupting chemicals (EDCs), in combination with environmental influences, interfere with endocrine function in humans and wildlife. Estrogens are a type of EDC that may alter the hypothalamic-pituitary-gonadal axis in male fathead minnows, Pimephales promelas. The impact of estrogens on P. promelas has been documented in previous laboratory exposures. Little is known, however, about the role the environment might play in modulating systemic upheaval resulting from estrogen exposure. A myriad of factors may influence estrogenic uptake and action. Due to this perplexity, the validity of laboratory experiments is often questioned. To address the issue, we examined the effects of diet and temperature on male P. promelas exposed to the common estrogen, estrone. An analysis of biological endpoints including plasma vitellogenin concentration, gonadosomatic index and histopathology indicated statistical trends. Gonad weights of fish kept at a water temperature of 17.9°C were significantly greater than fish kept at 26.3°C, lending evidence to a potential evolutionary link between gonad weight and water temperature. This may allow for reproductive fitness in cold water throughout the range of P. promelas. ELISA analysis determined that plasma vitellogenin (VTG) concentrations in fish exposed to 14.25 ng/L of estrone showed no real increase over control fish, while fish exposed to estrone concentrations of 71.45 ng/L showed a marked increase in plasma vitellogenin concentration. For this reason, VTG analysis may not be a useful endpoint for environmental concentrations below 14.25 ng/L. Furthermore, we anticipate that this experimental design might be a starting point from which aquatic toxicologists seek to modify laboratory exposures to generate more pertinent results with regards to their relevance to the natural environment of the model organism.

Technical Abstract: Endocrine-disrupting chemicals (EDCs), in combination with environmental influences, interfere with endocrine function in humans and wildlife. Estrogens are a type of EDC that may alter the hypothalamic-pituitary-gonadal axis in male fathead minnows, Pimephales promelas. The impact of estrogens on P. promelas has been documented in previous laboratory exposures. Little is known, however, about the role the environment might play in modulating systemic upheaval resulting from estrogen exposure. A myriad of factors may influence estrogenic uptake and action. Due to this perplexity, the validity of laboratory experiments is often questioned. To address the issue, we examined the effects of diet and temperature on male P. promelas exposed to the common estrogen, estrone. An analysis of biological endpoints including plasma vitellogenin concentration, gonadosomatic index and histopathology indicated statistical trends. Gonad weights of fish kept at a water temperature of 17.9°C were significantly greater than fish kept at 26.3°C, lending evidence to a potential evolutionary link between gonad weight and water temperature. This may allow for reproductive fitness in cold water throughout the range of P. promelas. ELISA analysis determined that plasma vitellogenin (VTG) concentrations in fish exposed to 14.25 ng/L of estrone showed no real increase over control fish, while fish exposed to estrone concentrations of 71.45 ng/L showed a marked increase in plasma vitellogenin concentration. For this reason, VTG analysis may not be a useful endpoint for environmental concentrations below 14.25 ng/L. Furthermore, we anticipate that this experimental design might be a starting point from which aquatic toxicologists seek to modify laboratory exposures to generate more pertinent results with regards to their relevance to the natural environment of the model organism.