EthoCRED: a framework to guide reporting and evaluation of the relevance and reliability of behavioural ecotoxicity studies.

Behavioural analysis has been attracting significant attention as a broad indicator of sub-lethal toxicity and has secured a place as an important subdiscipline in ecotoxicology. Among the most notable characteristics of behavioural research, compared to other established approaches in sub-lethal ecotoxicology (e.g.

Amphibian toxicity testing for identification of thyroid disrupting chemicals.

Both amphibian metamorphosis assay (AMA) and larval amphibian growth and development assay (LAGDA) can detect thyroid-mediated modality and adversity on the basis of morphological changes during the thyroid hormone-dependent metamorphosis. They are used for identification of thyroid hormone system disrupting chemicals (TDCs) for non-target organisms or the environment. The EU Guidance recommends that the AMA and the LAGDA should be used to address sufficient investigation of the thyroid-mediated modality and adversity, respectively.

Fish toxicity testing for identification of thyroid disrupting chemicals.

Identification of thyroid disrupting chemicals (TDCs), one of the most studied types of endocrine disruptors (EDs), is required according to EU regulations on industrial chemicals, pesticides, and biocides. Following that requirement, the use of fish as a unique non-mammalian model species for identification of EDs may be warranted. This study summarized and evaluated effects of TDCs on fish thyroid sensitive endpoints including thyroid hormones, thyroid related gene expression, immunostaining for thyroid follicles, eye size and pigmentation, swim bladder inflation as well as effects of TDCs on secondary sex characteristics, sex ratio, growth and reproduction.

The Role of Behavioral Ecotoxicology in Environmental Protection.

For decades, we have known that chemicals affect human and wildlife behavior. Moreover, due to recent technological and computational advances, scientists are now increasingly aware that a wide variety of contaminants and other environmental stressors adversely affect organismal behavior and subsequent ecological outcomes in terrestrial and aquatic ecosystems. There is also a groundswell of concern that regulatory ecotoxicology does not adequately consider behavior, primarily due to a lack of standardized toxicity methods.

Changes in fish sex ratio as a basis for regulating endocrine disruptors.

Fish sex ratio (SR) is an endpoint potentially indicating both endocrine activity and adversity, essential elements for identifying Endocrine Disrupting Chemicals (EDCs) as required by the EU regulations. Due to different protocols and methods in the literature studies, SR data vary greatly. This study analyses literature SR data and discusses important considerations for using SR data in the regulatory context for the hazard identification, classification, PBT (persistent, bioaccumulative and toxic) assessment, testing, and risk assessment.

Endpoint sensitivity in Amphibian Metamorphosis Assay.

The Amphibian Metamorphosis Assay (AMA) is a screening test for detecting chemicals with thyroid activity. There is little experience in data interpretation and in using AMA data for screening, testing and identifying endocrine disruptors. To investigate the sensitivity of different endpoints of the AMA, the publically available data for 57 thyroid active and inactive chemicals were compiled and analyzed.

Applicability of the fish embryo acute toxicity (FET) test (OECD 236) in the regulatory context of Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH).

In 2013 the Organisation for Economic Co-operation and Development (OECD) test guideline (236) for fish embryo acute toxicity (FET) was adopted. It determines the acute toxicity of chemicals to embryonic fish. Previous studies show a good correlation of FET with the standard acute fish toxicity (AFT) test; however, the potential of the FET test to predict AFT, which is required by the Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH) regulation (EC 1907/2006) and the Classification, Labelling and Packaging (CLP) Regulation (EC 1272/2008), has not yet been fully clarified.

Fish embryo toxicity test, threshold approach, and moribund as approaches to implement 3R principles to the acute fish toxicity test.

The acute fish toxicity test (AFT) is requested by EU legal frameworks for hazard classification and risk assessment. AFT is one of the few regulatory required tests using death as an endpoint. This paper reviews efforts made to reduce, refine and replace (3Rs) AFT.

Recommended approaches to the scientific evaluation of ecotoxicological hazards and risks of endocrine-active substances.

A SETAC Pellston Workshop "Environmental Hazard and Risk Assessment Approaches for Endocrine-Active Substances (EHRA)" was held in February 2016 in Pensacola, Florida, USA. The primary objective of the workshop was to provide advice, based on current scientific understanding, to regulators and policy makers; the aim being to make considered, informed decisions on whether to select an ecotoxicological hazard- or a risk-based approach for regulating a given endocrine-disrupting substance (EDS) under review. The workshop additionally considered recent developments in the identification of EDS.

Challenges in assigning endocrine-specific modes of action: Recommendations for researchers and regulators.

As regulatory programs evaluate substances for their endocrine-disrupting properties, careful study design and data interpretation are needed to distinguish between responses that are truly endocrine specific and those that are not. This is particularly important in regulatory environments where criteria are under development to identify endocrine-disrupting properties to enable hazard-based regulation. Irrespective of these processes, most jurisdictions use the World Health Organization/International Programme on Chemical Safety definition of an endocrine disruptor, requiring that a substance is demonstrated to cause a change in endocrine function that consequently leads to an adverse effect in an intact organism.

Interpretation of fish biomarker data for identification, classification, risk assessment and testing of endocrine disrupting chemicals.

Chemical induced changes in fish biomarkers vitellogenin (VTG), secondary sex characteristics (SSC), and sex ratio indicate modes/mechanisms of action (MOAs) of EAS (estrogen, androgen and steroidogenesis) pathways. These biomarkers could be used for defining MOAs and the causal link between MOAs and adverse effects in fish for the identification of endocrine disrupting chemicals (EDCs). This paper compiled data sets of 150 chemicals for VTG, 57 chemicals for SSC and 38 chemicals for sex ratio in fathead minnow, medaka and zebrafish.

Fish biomarkers for regulatory identification of endocrine disrupting chemicals.

Demonstrating chemical-induced adverse effects, endocrine mechanisms/modes of action (MOAs) and their causal link is needed for regulatory identification of endocrine disrupting chemicals (EDCs). This paper addresses critical issues over MOAs and their causal link to changes in endpoints. Vitellogenin (VTG), secondary sex characteristics (SSC), and sex ratio (also an apical endpoint) are indicative of chemicals interfering with EAS (estrogen, androgen and steroidogenesis) pathways.

[Effects of perfluorooctane sulfonate (PFOS) exposure on vitellogenin mRNA level in zebrafish (Brachydanio rerio)].

To study the endocrine disrupting effects and action mechanism of environmental levels of perfluorooctane sulfonate (PFOS) on the aquatic species, the research for the effects of PFOS exposure on vitellogenin (VTG) mRNA level in livers of zebrafish (Brachydanio rerio) was conducted. Zebrafish were exposed to PFOS at four environmental low concentrations (0.1, 1, 10, 100 microg x L(-1)) for 21 days.

Evaluation of the Daphnia magna reproduction test for detecting endocrine disruptors.

The Daphnia 21 d reproduction test is considered as a comprehensive and decisive test in the OECD Conceptual Framework for testing and assessment of endocrine disrupting chemicals (EDCs). However, how to interpret results of the Daphnia 21 d reproduction test for identification, risk assessment and testing strategy of EDCs remains an unsolved issue. This study analysed a total number of 135 published studies encompassing 86 known EDCs and non-EDCs with different modes of action.

Evaluation of the fish short term reproduction assay for detecting endocrine disrupters.

In a fish testing strategy, positive results of the fish short term reproduction assay (FSTR), often trigger a definitive test like the fish sexual development test (FSDT) or the fish full life cycle test (FFLC), entailing ethical and economic problems. This study analysed 137 studies encompassing 35 chemicals with different modes of actions (MOAs). Variability is quantified for MOA endpoints vitellogenin (VTG) and secondary sex characteristics (SSCs) as well as for apical endpoints.

Endpoint sensitivity in fish endocrine disruption assays: regulatory implications.

Identifying potential endocrine disrupting chemicals (EDCs) needs screening and testing for mode of action (MOA) and intrinsic toxicological properties. MOA is often indicated by biomarker endpoints, whereas toxicity by apical endpoints. Risk assessment is mainly based on apical but not on biomarker endpoints.

Comparison of chemical-induced transcriptional activation of fish and human estrogen receptors: regulatory implications.

Under the current EU chemical regulation REACH (Registration, Evaluation, Authorization and Restriction of Chemicals), revised plant protection products and biocides directives, evaluation of endocrine disrupting properties of chemicals becomes a regulatory need. Transcriptional activation (TA) testing of estrogen receptors (ERs) could be one important first step in the screening and testing of endocrine disrupting chemicals (EDCs) for regulatory purposes. However up to now there is no consensus on which species or subtype of ERs should be used for TA testing.

An Integrated Assessment Scheme for assessing the adequacy of (eco)toxicological data under REACH.

REACH requires all available (eco)toxicological information, whether protocol studies, other experiments, or non-testing approaches such as read-across or (Q)SAR, to be collected and evaluated. However, guidance documents only limitedly address how adequacy of (eco)toxicological information can be assessed consistently and transparently. We propose an Integrated Assessment Scheme (IAS) for the evaluation of (eco)toxicological data.

Comparison of relative binding affinities to fish and mammalian estrogen receptors: the regulatory implications.

Screening and testing of chemicals binding to estrogen receptors (ERs) emerge as an important issue in several regulatory programs or frameworks. Discrepancies exist, however, whether fish ERs should be included in the regulatory programs. In view of the differences in binding affinities to ERalpha and ERbeta and the significant contribution of ERbeta to biological effects of chemicals, it remains unknown whether both types of ERs are needed for the regulatory purposes.

Retrospective analysis of relative parameter sensitivity in multi-generation reproductive toxicity studies.

Current suggestions towards amending the OECD two-generation protocol include omission of the second generation and inclusion of additional parameters. This study analysed the relative parameter sensitivity in 18 individually published multi-generation studies with substances toxic to fertility. Among parameters that most often determined the reproductive LOAEL were weight of testis, dam and pup as well as litter size.

Sixteen hours of fasting differentially affects hepatic and muscle insulin sensitivity in mice.

Fasting readily induces hepatic steatosis. Hepatic steatosis is associated with hepatic insulin resistance. The purpose of the present study was to document the effects of 16 h of fasting in wild-type mice on insulin sensitivity in liver and skeletal muscle in relation to 1) tissue accumulation of triglycerides (TGs) and 2) changes in mRNA expression of metabolically relevant genes.

Differential effects of PD98059 and U0126 on osteogenesis and adipogenesis.

PD98059 and U0126 are considered as specific inhibitors of the p42/44 mitogen-activated protein kinases (MAPK) pathway, which affects osteogenesis and adipogenesis. Here, we show unexpected differential effects of PD98059 and U0126 on osteogenesis and adipogenesis as well as on estrogen (E2)-induced actions in osteoprogenitor KS483 cells. PD98059 dose-dependently inhibited osteogenesis indicated by cellular alkaline phosphatase (ALP) activity and nodule formation, but stimulated adipogenesis shown by the number of adipocytes.

The balance between concurrent activation of ERs and PPARs determines daidzein-induced osteogenesis and adipogenesis.

Unlabelled: The soy phytoestrogen daidzein has biphasic dose responses, but the underlying mechanisms are not yet clear. Transcriptional and biochemical data show that PPARs, in addition to ERs, are molecular targets of daidzein, which divergently regulates osteogenesis and adipogenesis. Dose responses are the result of a balance among PPARs and between ERs and PPARs.

Peroxisome proliferator-activated receptor gamma (PPARgamma ) as a molecular target for the soy phytoestrogen genistein.

The principal soy phytoestrogen genistein has an array of biological actions. It binds to estrogen receptor (ER) alpha and beta and has ER-mediated estrogenic effects. In addition, it has antiestrogenic effects as well as non-ER-mediated effects such as inhibition of tyrosine kinase.