Regulatory approaches to endocrine disrupting (ED) chemicals have been hampered by the slow development of internationally validated testing methods and the UK has been active in assisting the OECD Chemicals Programme to address this. In conjunction, there is pressure to reduce the usage of laboratory animals in testing, or at least minimise their stress, particularly in view of the development of the new European Chemicals Strategy (REACH).
The OECD is currently validating the Hershberger assay; this identifies potential anti-androgens (which block the action of masculinising hormones) using surgically castrated male rats. However, an alternative assay has been developed using testosterone-stimulated weanlings, which avoids the need for castration with no loss of comparative sensitivity . The new test would eliminate a specific surgical trauma to young rats, thus enhancing their welfare. The OECD Validation Management Group (VMG) has accepted the new assay into validation along side the Hershberger assay, but there are no resources available for laboratories to participate in its validation - even though the European industry organization CEFIC had provided funding for laboratories to validate the Hershberger and uterotrophic assays.
To date, the first phase of validation has been completed by the Syngenta laboratory in the UK and collaborating laboratories in Canada and Korea. This project aims to enable the completion of a scientifically sound validation of the new assay and the presentation of the results to the OECD VMG, by making possible the participation of the UK Syngenta laboratory and an appropriate number of suitably proficient collaborators in the main phase of the project.