Dataset Information

Dietary exposure of 17-alpha ethinylestradiol modulates physiological endpoints and gene signaling pathways in female largemouth bass (Micropterus salmoides).

ABSTRACT: 17Alpha-ethinylestradiol (EE2), used for birth control in humans, is a potent estrogen that is found in wastewater at low concentrations (ng/l). EE2 has the ability to interfere with the endocrine system of fish, affecting reproduction which can result in population level effects. The objective of this study was to determine if dietary exposure to EE2 would alter gene expression patterns and key pathways in the liver and ovary and whether these could be associated with reproductive endpoints in female largemouth bass during egg development. Female LMB received 70ng EE2/g feed (administered at 1% of body weight) for 60 days. EE2 dietary exposure significantly reduced plasma vitellogenin concentrations by 70%. Hepatosomatic and gonadosomatic indices were also decreased with EE2 feeding by 38.5% and 40%, respectively. Transcriptomic profiling revealed that there were more changes in steady state mRNA levels in the liver compared to the ovary. Genes associated with reproduction were differentially expressed, such as vitellogenin in the liver and aromatase in the gonad. In addition, a set of genes related with oxidative stress (e.g. glutathione reductase and glutathione peroxidase) were identified as altered in the liver and genes associated with the immune system (e.g. complement component 1, and macrophage-inducible C-type lectin) were altered in the gonad. In a follow-up study with 0.2ng EE2/g feed for 60 days, similar phenotypic and gene expression changes were observed that support these findings with the higher concentrations. This study provides new insights into how dietary exposure to EE2 interferes with endocrine signaling pathways in female LMB during a critical period of reproductive oogenesis.

SUBMITTER: Colli-Dula RC

PROVIDER: S-EPMC4252624 | biostudies-literature | 2014 Nov

REPOSITORIES: biostudies-literature

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Dietary exposure of 17-alpha ethinylestradiol modulates physiological endpoints and gene signaling pathways in female largemouth bass (Micropterus salmoides).

Colli-Dula Reyna-Cristina RC Martyniuk Christopher J CJ Kroll Kevin J KJ Prucha Melinda S MS Kozuch Marianne M Barber David S DS Denslow Nancy D ND

Aquatic toxicology (Amsterdam, Netherlands) 20140827

17Alpha-ethinylestradiol (EE2), used for birth control in humans, is a potent estrogen that is found in wastewater at low concentrations (ng/l). EE2 has the ability to interfere with the endocrine system of fish, affecting reproduction which can result in population level effects. The objective of this study was to determine if dietary exposure to EE2 would alter gene expression patterns and key pathways in the liver and ovary and whether these could be associated with reproductive endpoints in ...[more]

PMID: 25203422

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Project description:BackgroundOocyte maturation in fish involves numerous cell signaling cascades that are activated or inhibited during specific stages of oocyte development. The objectives of this study were to characterize molecular pathways and temporal gene expression patterns throughout a complete breeding cycle in wild female largemouth bass to improve understanding of the molecular sequence of events underlying oocyte maturation.MethodsTranscriptomic analysis was performed on eight morphologically diverse stages of the ovary, including primary and secondary stages of oocyte growth, ovulation, and atresia. Ovary histology, plasma vitellogenin, 17β-estradiol, and testosterone were also measured to correlate with gene networks.ResultsGlobal expression patterns revealed dramatic differences across ovarian development, with 552 and 2070 genes being differentially expressed during both ovulation and atresia respectively. Gene set enrichment analysis (GSEA) revealed that early primary stages of oocyte growth involved increases in expression of genes involved in pathways of B-cell and T-cell receptor-mediated signaling cascades and fibronectin regulation. These pathways as well as pathways that included adrenergic receptor signaling, sphingolipid metabolism and natural killer cell activation were down-regulated at ovulation. At atresia, down-regulated pathways included gap junction and actin cytoskeleton regulation, gonadotrope and mast cell activation, and vasopressin receptor signaling and up-regulated pathways included oxidative phosphorylation and reactive oxygen species metabolism. Expression targets for luteinizing hormone signaling were low during vitellogenesis but increased 150% at ovulation. Other networks found to play a significant role in oocyte maturation included those with genes regulated by members of the TGF-beta superfamily (activins, inhibins, bone morphogenic protein 7 and growth differentiation factor 9), neuregulin 1, retinoid X receptor, and nerve growth factor family.ConclusionsThis study offers novel insight into the gene networks underlying vitellogenesis, ovulation and atresia and generates new hypotheses about the cellular pathways regulating oocyte maturation.

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Dataset Information

Dietary exposure of 17-alpha ethinylestradiol modulates physiological endpoints and gene signaling pathways in female largemouth bass (Micropterus salmoides).

Publications

Dietary exposure of 17-alpha ethinylestradiol modulates physiological endpoints and gene signaling pathways in female largemouth bass (Micropterus salmoides).

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