Endocrine disruption in fish - new testing concept with molecular markers

© Fraunhofer IME

Endocrine disrupting substances are perceived by the general public as particularly threatening. Therefore, much effort is spent on the definition of endocrine effects and on developing test procedures focusing on the assessment of these effects. Pesticide legislation (EC 1107/2009) as well as the European Union regulation on chemicals (REACH) require that substances need to be tested for their potential to act as endocrine disruptors. The introduction of a “cut-off” criterion for endocrine disrupting substances in EC 1107/2009 underlines the importance of this topic for the industry. Concerning the environmental effects of endocrine disruptors the focus is on aquatic vertebrates.
Studies in fish, e.g., concentrate on sexual endocrine effects which can cause hormone imbalance and have a harmful effect on fish development and reproduction. The identification of endocrine disruptors is usually both time-consuming and expensive and involves the use of large numbers of test animals. At the same time, the number of possible endocrine disruptors requiring registration is growing. There is therefore a drive to develop new concepts to meet these demands. One concept, entitled Adverse Outcome Pathways (AOP) sets out to discover what takes place between an initial molecular event and a subsequent negative effect on an individual or a whole population. Applying this concept to the field of ecotoxicology could be very promising. Fraunhofer IME has conducted a study which was intended to evaluate whether gene expression endpoints would serve as predictive markers of endocrine disruption in a FSDT (Fish Sexual Development Test: non-reproductive test to assess adverse effects of endocrine disrupting chemicals).