Science Inventory

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Endocrine disrupting chemicals are a diverse set of substances that have the potential to interfere with normal endocrine function and lead to an adverse outcome. The defined approach (DA) presented in this document describes an integrated testing strategy (ITS) for the identific...

The advantage of applying a defined approach (DA) to inform a widespread issue like endocrine disruption is that DAs are fixed approaches that do not rely on expert judgement, so yield predictable results. As such, these may then be developed into OECD test guidelines as part of ...

Androgen receptor (AR) antagonism is a mechanism of endocrine disruption by environmental chemicals that is associated with a number of adverse effects including reproductive organ cancers and abnormalities. To identify chemicals that may act as AR antagonists, quantitative high-...

Presentation given at North Carolina State University Oct 31, 2017

Altered androgen hormone biosynthesis and metabolism can modulate androgen levels, contributing to endocrine disruption that may result in impaired reproductive and sexual development. Steroid 5α-reductase isozymes are expressed in key peripheral tissues and catalyze the conversi...

Brominated flame retardants (BFRs) and perfluorinated chemicals (PFCs) belong to a class of chemicals known as organohalogens. It is believed that use of both BFRs and PFCs has resulted in lives saved by reducing flammability of materials commonly used and also due to their bacte...

ABSTRACTWorldwide concern about the impacts of endocrine disrupting compounds on both human and environmental health has led to implementation of multiple screening and testing programs. In most cases these programs have focused on impacts to the estrogen, androgen and thyroid h...

This abstract will be submitted for the consideration of either a poster or platform presentation at the 2018 Annual Carolinas Society of Environmental Toxicology and Chemistry held in Research Triangle Park, NC April 25-27th.

High-throughput transcriptomic (HTTr) technologies are increasingly being used to screen environmental chemicals in vitro to provide mechanistic context for regulatory testing. The development of gene expression biomarkers that accurately predict molecular and toxicological effec...

There is significant concern regarding potential impairment of fish reproduction associated with exposure to endocrine disrupting chemicals (EDCs). Aromatase is a steroidogenic enzyme involved in the conversion of androgens to estrogens. Inhibition of aromatase activity by exposu...

Disruption of thyroid hormone signaling is a form of endocrine disruption that is of concern to both human health and ecosystems. Research is being conducted to define the biological targets chemicals may interact with to disrupt thyroid hormone signaling and the stages in develo...

To date, most research focused on developing more efficient and cost effective methods to predict toxicity have focused on human biology. However, there is also a need for effective high throughput tools to predict toxicity to other species that perform critical ecosystem functio...

Gene expression, enzyme activities, changes in endogenous metabolite or hormone titers, altered histology, etc. are widely used as biomarkers, but rarely, if ever, used for regulatory decision-making or to define management objectives. The disconnect between the measurements comm...

The flexible hydrophobic ligand binding pocket (LBP) of estrogen receptor α (ERα) allows the binding of a wide variety of endocrine disruptors. Upon ligand binding, the LBP reshapes around the contours of the ligand and stabilizes the complex by complementary hydrophobic interact...

Testing thousands of chemicals to identify potential androgen receptor (AR) agonists or antagonists would cost millions of dollars and take decades to complete using current validated methods. High-throughput in vitro screening (HTS) and computational toxicology approaches can mo...

The US EPA is charged with screening chemicals for their ability to be endocrine disruptors through interaction with the estrogen, androgen and thyroid axes. The agency is starting to explore the use of high-throughput in vitro assays to use in the Endocrine Disruptor Screening P...

Cytochrome P450 aromatase catalyzes conversion of C19 androgens to C18 estrogens and is critical for normal reproduction in female vertebrates. Fadrozole is a well-studied aromatase inhibitor that has been shown to suppress estrogen production in the ovaries of fish. However, l...

Triclocarban (TCC) is a widely used antimicrobial agent that is routinely detected in surface waters. The present study was designed to examine TCC’s efficacy and mode of action as a reproductive toxicant in fish. Reproductively mature Pimephales promelas were continuously expose...

Environmental assessment of complex mixtures typically requires integration of chemical and biological measurements. This study demonstrates the use of a combination of instrumental chemical analyses, effects-based monitoring, and bio-effects prediction approaches to help identi...

Efforts are underway to transform regulatory toxicology and chemical safety assessment from a largely empirical science based on direct observation of apical toxicity outcomes in whole organism toxicity tests to a predictive one in which outcomes and risk are inferred from accumu...

In this paper existing regulatory frameworks and test systems for assessing potential endocrine-active chemicals are described, and associated challenges discussed, along with proposed approaches to address these challenges. Regulatory frameworks vary somewhat across organizatio...

Molting is a key biological process in growth, development, reproduction and survival in arthropods. Complex neuroendocrine pathways are involved in the regulation of molting and may potentially become targets of environmental endocrine disrupting compounds (EDCs). For example, s...

The potential for chemicals to affect endocrine signaling is commonly evaluated via in vitro receptor binding and gene activation, but these assays, especially antagonism assays, have potential artifacts that must be addressed for accurate interpretation. Results are presented fr...

We examined whether contaminants present in surface waters could be prioritized for further assessment by linking the presence of specific chemicals to gene expression changes in exposed fish. Fathead minnows were deployed in cages for 2, 4, or 8 days at three locations near two ...

In response to various legislative mandates the United States Environmental Protection Agency (USEPA) formed its Endocrine Disruptor Screening Program (EDSP), which in turn, implemented a tiered testing strategy to determine the potential of pesticides, commercial chemicals, and ...