ID#

1071

Location:

Exhibit Hall

Time of Presentation:

March 11, 2003 - 1:30 p.m.

Category (Subcategory):

In Vitro/Alternative Animal Models, (Reproductive System), (Nuclear and Cytosolic Receptors)

ICCVAM/NICEATM Expert Panel Recommendations for the Standardization and Validation of In Vitro Estrogen Receptor (ER) and Androgen Receptor (AR) Transcriptional Activation (TA) Assays
B.S. Shane^1,2; J. Stegeman³; E.M. Wilson⁴; C.J. Inhof^1,2;
R.R. Tice^1,2; E. Zeiger⁵; W.S. Stokes²
1. ILS, Inc., RTP, NC, USA;
2. NICEATM, NIEHS , RTP, NC, USA;
3. Woods Hole Oceanographic Institute, Woods Hole, MA, USA;
4. Univ. of N. C., Chapel Hill, NC, USA;
5. Errol Zeiger Consulting, Chapel Hill, NC, USA;

A variety of natural and anthropogenic substances appear to interact with the endocrine system. As a result, the U.S. EPA was required by legislation to develop a screening and testing program to identify substances with endocrine disruptor (ED) activity. Within the Tier 1 battery of screening test methods, in vitro ER and AR TA assays are proposed to identify estrogenic or androgenic agonists or antagonists. In vitro results would be considered together with other Tier 1 assay results in a weight-of-evidence evaluation of the need for testing in the more definitive Tier 2 in vivo assays. A comprehensive literature review indicated no adequately validated in vitro ER or AR TA assays. After considering the available data, an ICCVAM/NICEATM-sponsored Expert Panel developed recommendations for future development, standardization, and validation efforts. For ER TA assays, a mammalian cell line transfected with a human ER expression vector and a luciferase reporter containing multiple vitellogenin estrogen response elements is recommended. Pre-validation studies should be performed to determine whether transiently or stably transfected cell lines are most useful. For AR TA assays, validation of a mammalian cell line containing an endogenous human AR and transduced with an adenovirus containing a luciferase reporter plasmid is recommended. Recommendations were also developed for minimum procedural standards and substances for validation studies, which together should facilitate standardization and validation of protocols for ER and AR TA assays. Supported by NIEHS Contract N01-ES-85424.