National Toxicology Program

Overview and Related Links

In April 2000, the EPA asked ICCVAM to evaluate the validation status of in vitro endocrine disruptor screening assays, which were proposed as possible components of the EPA's Endocrine Disruptor Screening Program. NICEATM subsequently compiled available relevant data and prepared a comprehensive Background Review Document (BRD) for each of the four types of assay. An independent expert panel review concluded that there were no adequately validated in vitro endocrine disruptor screening assays.

Based on the expert panel’s conclusions and recommendations, along with comments from the public, ICCVAM developed recommendations for minimum procedural standards and test methods for future validation of in vitro estrogen receptor (ER) and androgen receptor (AR) binding and transcriptional activation (TA) assays. These recommendations were made publicly available in the Test Method Evaluation Report, and included:

• Assay development emphasizing the use of recombinant-derived ER and AR rather that animal-derived proteins
• More detailed research and study into methods for making statistical inferences with in vitro endocrine disruptor data
• Review of the available information on the degree to which metabolism is known to alter estrogenic and androgenic activity in vivo

The ICCVAM report also included a list of 78 reference substances that should be used to standardize and validate these assays, and the following recommendations regarding the use of these substances:

• Use of all 78 substances in the validation of each in vitro assay to more accurately assess the predictive value of the assay
• Organization of a central repository for samples of the 78 substances that have had purity verified

The list of 78 reference substances was subsequently modified because of cost and availability considerations and published in a separate Addendum.

Links to Sites with More Information about Endocrine Disruptor Research

The links listed below connect to pages outside the NICEATM/ICCVAM website. These links are for the convenience of visitors to this page, who may find them useful. NICEATM/ICCVAM is not responsible for the availability or content of these external sites, nor do we endorse, warrant or guarantee any information or any products or services described or offered at these other sites.

• Endocrine Disruptor Research in the European Union
  European Commission's Directorate-General of Research website, which focuses on endocrine disrupter research in Europe



• CREDO - Cluster of Research into Endocrine Disruption in Europe
  Four projects funded by the European Union form the core of the CREDO cluster: EDEN, COMPRENDO, EURISKED and FIRE



• IPCS (The International Programme on Chemical Safety, sponsored by the World Health Organization)


• Press release: Endocrine Disrupting Chemicals: New Publication Shows Need For Further Research



• Report: Global Assessment of the State-of-the-Science of Endocrine Disruptors (WHO/PCS/EDC/02.2).



• EPA's Endocrine Disruptor Screening Program (EDSP)



• EPA's Endocrine Disruptor Methods Validation Subcommittee (EDMVS)



• EPA Federal Register Notice (Vol. 66, No. 88, pp. 23022-23027, May 7, 2001): Endocrine Disruptor Screening Program; Establishment of an Endocrine Disruptor Methods Validation Subcommittee under the National Advisory Council for Environmental Policy and Technology; Request for Nominations for Membership. This document can be found via the EDSP Federal Register Notices page.