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Gene expression responses in male fathead minnows exposed to binary mixtures of an estrogen and antiestrogen.

Garcia-Reyero N, Kroll KJ, Liu L, Orlando EF, Watanabe KH, Sepúlveda MS, Villeneuve DL, Perkins EJ, Ankley GT, Denslow ND - BMC Genomics (2009)

Bottom Line: Aquatic organisms are continuously exposed to complex mixtures of chemicals, many of which can interfere with their endocrine system, resulting in impaired reproduction, development or survival, among others.In order to analyze the effects and mechanisms of action of estrogen/anti-estrogen mixtures, we exposed male fathead minnows (Pimephales promelas) for 48 hours via the water to 2, 5, 10, and 50 ng 17alpha-ethinylestradiol (EE2)/L, 100 ng ZM 189,154/L (a potent antiestrogen known to block activity of estrogen receptors) or mixtures of 5 or 50 ng EE(2)/L with 100 ng ZM 189,154/L.Steroidogenesis was down-regulated by EE(2) as reflected by the reduced plasma levels of testosterone in the exposed fish and down-regulation of genes in the steroidogenic pathway.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611, USA. natalia@ccmsi.us

ABSTRACT

Background: Aquatic organisms are continuously exposed to complex mixtures of chemicals, many of which can interfere with their endocrine system, resulting in impaired reproduction, development or survival, among others. In order to analyze the effects and mechanisms of action of estrogen/anti-estrogen mixtures, we exposed male fathead minnows (Pimephales promelas) for 48 hours via the water to 2, 5, 10, and 50 ng 17alpha-ethinylestradiol (EE2)/L, 100 ng ZM 189,154/L (a potent antiestrogen known to block activity of estrogen receptors) or mixtures of 5 or 50 ng EE(2)/L with 100 ng ZM 189,154/L. We analyzed gene expression changes in the gonad, as well as hormone and vitellogenin plasma levels.

Results: Steroidogenesis was down-regulated by EE(2) as reflected by the reduced plasma levels of testosterone in the exposed fish and down-regulation of genes in the steroidogenic pathway. Microarray analysis of testis of fathead minnows treated with 5 ng EE(2)/L or with the mixture of 5 ng EE(2)/L and 100 ng ZM 189,154/L indicated that some of the genes whose expression was changed by EE(2) were blocked by ZM 189,154, while others were either not blocked or enhanced by the mixture, generating two distinct expression patterns. Gene ontology and pathway analysis programs were used to determine categories of genes for each expression pattern.

Conclusion: Our results suggest that response to estrogens occurs via multiple mechanisms, including canonical binding to soluble estrogen receptors, membrane estrogen receptors, and other mechanisms that are not blocked by pure antiestrogens.

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Related in: MedlinePlus

Pathway Studio analysis. (A) Competitive interactome consisting of genes that are regulated by 5 ng EE2/L and blocked by the mixture of 5 ng EE2/L and 100 ng ZM/L. (B) Non-competitive interactome consisting of genes that are regulated by 5 ng EE2/L but either not changed or enhanced by the mixture of 5 ng EE2/L and 100 ng ZM/L. Red indicates up-regulation, green indicates down-regulation.
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Figure 6: Pathway Studio analysis. (A) Competitive interactome consisting of genes that are regulated by 5 ng EE2/L and blocked by the mixture of 5 ng EE2/L and 100 ng ZM/L. (B) Non-competitive interactome consisting of genes that are regulated by 5 ng EE2/L but either not changed or enhanced by the mixture of 5 ng EE2/L and 100 ng ZM/L. Red indicates up-regulation, green indicates down-regulation.

Mentions: An interactome is defined as a set of genes whose protein products are functionally linked together either by direct binding, regulation of activity, regulation of expression, promoter binding, protein modification or molecular transport [48]. Using the databases available in PubMed at NCBI (National Center for Biotechnology Information, ), we have identified interactomes for both the genes that were regulated by EE2 and then blocked by the combination of EE2 and ZM (Figure 6A – called "competitive interactome" in the discussion below), and those that were regulated by EE2 and either not affected by ZM or enhanced (in either direction) by the combination (Figure 6B – called "non-competitive interactome"). We analyzed these separately in order to determine the types of genes that were included in each.


Gene expression responses in male fathead minnows exposed to binary mixtures of an estrogen and antiestrogen.

Garcia-Reyero N, Kroll KJ, Liu L, Orlando EF, Watanabe KH, Sepúlveda MS, Villeneuve DL, Perkins EJ, Ankley GT, Denslow ND - BMC Genomics (2009)

Pathway Studio analysis. (A) Competitive interactome consisting of genes that are regulated by 5 ng EE2/L and blocked by the mixture of 5 ng EE2/L and 100 ng ZM/L. (B) Non-competitive interactome consisting of genes that are regulated by 5 ng EE2/L but either not changed or enhanced by the mixture of 5 ng EE2/L and 100 ng ZM/L. Red indicates up-regulation, green indicates down-regulation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2713996&req=5

Figure 6: Pathway Studio analysis. (A) Competitive interactome consisting of genes that are regulated by 5 ng EE2/L and blocked by the mixture of 5 ng EE2/L and 100 ng ZM/L. (B) Non-competitive interactome consisting of genes that are regulated by 5 ng EE2/L but either not changed or enhanced by the mixture of 5 ng EE2/L and 100 ng ZM/L. Red indicates up-regulation, green indicates down-regulation.
Mentions: An interactome is defined as a set of genes whose protein products are functionally linked together either by direct binding, regulation of activity, regulation of expression, promoter binding, protein modification or molecular transport [48]. Using the databases available in PubMed at NCBI (National Center for Biotechnology Information, ), we have identified interactomes for both the genes that were regulated by EE2 and then blocked by the combination of EE2 and ZM (Figure 6A – called "competitive interactome" in the discussion below), and those that were regulated by EE2 and either not affected by ZM or enhanced (in either direction) by the combination (Figure 6B – called "non-competitive interactome"). We analyzed these separately in order to determine the types of genes that were included in each.

Bottom Line: Aquatic organisms are continuously exposed to complex mixtures of chemicals, many of which can interfere with their endocrine system, resulting in impaired reproduction, development or survival, among others.In order to analyze the effects and mechanisms of action of estrogen/anti-estrogen mixtures, we exposed male fathead minnows (Pimephales promelas) for 48 hours via the water to 2, 5, 10, and 50 ng 17alpha-ethinylestradiol (EE2)/L, 100 ng ZM 189,154/L (a potent antiestrogen known to block activity of estrogen receptors) or mixtures of 5 or 50 ng EE(2)/L with 100 ng ZM 189,154/L.Steroidogenesis was down-regulated by EE(2) as reflected by the reduced plasma levels of testosterone in the exposed fish and down-regulation of genes in the steroidogenic pathway.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611, USA. natalia@ccmsi.us

ABSTRACT

Background: Aquatic organisms are continuously exposed to complex mixtures of chemicals, many of which can interfere with their endocrine system, resulting in impaired reproduction, development or survival, among others. In order to analyze the effects and mechanisms of action of estrogen/anti-estrogen mixtures, we exposed male fathead minnows (Pimephales promelas) for 48 hours via the water to 2, 5, 10, and 50 ng 17alpha-ethinylestradiol (EE2)/L, 100 ng ZM 189,154/L (a potent antiestrogen known to block activity of estrogen receptors) or mixtures of 5 or 50 ng EE(2)/L with 100 ng ZM 189,154/L. We analyzed gene expression changes in the gonad, as well as hormone and vitellogenin plasma levels.

Results: Steroidogenesis was down-regulated by EE(2) as reflected by the reduced plasma levels of testosterone in the exposed fish and down-regulation of genes in the steroidogenic pathway. Microarray analysis of testis of fathead minnows treated with 5 ng EE(2)/L or with the mixture of 5 ng EE(2)/L and 100 ng ZM 189,154/L indicated that some of the genes whose expression was changed by EE(2) were blocked by ZM 189,154, while others were either not blocked or enhanced by the mixture, generating two distinct expression patterns. Gene ontology and pathway analysis programs were used to determine categories of genes for each expression pattern.

Conclusion: Our results suggest that response to estrogens occurs via multiple mechanisms, including canonical binding to soluble estrogen receptors, membrane estrogen receptors, and other mechanisms that are not blocked by pure antiestrogens.

Show MeSH
Related in: MedlinePlus