Publication Abstract

Summary of the in vivo stickleback tests aimed to be part of the official OECD guidelines for endocrine disruptor testing.

Ioanna Katsiadaki*, Yvonne Allen*, Ian Mayer, Tom G. Pottinger, Matthew B. Sanders*, Marion Sebire*, Alexander P. Scott*

The internationally standardised chemical testing regimes were not specifically designed for identifying endocrine disrupting chemicals (EDCs) and are certainly inadequate for estimating their likely ecological or medical effects. This problem has caused the Organization for Economic Cooperation and Development (OECD) to expand its test guideline development programme and include procedures that can identify EDCs. In the case of fish, the OECD developed (and is close to validating) a 21-day screening test guideline, which is sensitive to certain EDCs (oestrogens/androgens and their antagonists, plus aromatase inhibitors). In this screen the proposed species are the Japanese medaka, the fathead minnow and the zebrafish. 

The adoption of the guideline as the main screen for the detection of EDCs recommended by the OECD presents three major limitations. The first is specific to European countries and is related to the fact that none of the proposed species is endemic in Europe, rendering data extrapolation obtained from model species to environmental risk assessment problematic. The second issue is universal and related to the lack of robust endpoints in the three core species that have a diagnostic value for androgenic xenobiotics (in particular androgen antagonists). The third is the fact that the core laboratory species do not display an annual reproductive cycle, as in the case of the vast majority of fish, which makes the screen of limited value for environmental risk assessment.

In view of these limitations, the potential of the stickleback as a model species for EDCs testing was evaluated in a series of tests and their responses are presented. The studies include two international ring tests.