Multi-endpoint studies are currently in use to test for mammalian toxicity; all are performed in the rat and include the following: 1 and 2 generation studies Additionally, several fish and invertebrate apical studies look at the full life cycle and specifically at reproductive Tariquidar datasheet endpoints to test for ecotoxicity of potential endocrine disruptors. Two recent initiatives have dealt with defining endocrine disrupting properties for the purposes of regulation: The ECETOC Workshop on 25–26 June 2009 in Barcelona and the BfR Workshop on 11–13 November 2009 in Berlin (see Hirsch-Ernst presentation below). The remainder of this presentation focused

on the ECETOC proposal (ECETOC, 2009). The ECETOC approach considers the Weybridge definition of endocrine disruption and the principles of mode of action, specificity and potency of the potential endocrine

disrupter. ECETOC further asks us to examine the weight of scientific evidence, the human relevance and the assessment of risk of a pesticide with potential endocrine disrupting properties. The ECETOC approach is centred on a generic flowchart: first is a 5-step approach to identify an endocrine disruptor from a mammalian dataset and second is guidance on how to deal with specificity and potency in order to discriminate chemicals of high concern, low concern and no concern. Only when a positive outcome in one or more endocrine LY294002 sensitive endpoints is supported by mechanism of action (MoA) data (in vitro and in vivo studies)

i.e., the Screening Library cell line sequence of the biochemical and cellular events that underlies the adverse effect is described and understood, then conclusive proof of endocrine disruption can be considered as established. Five potential scenarios are presented in Fig. 2 (A–E). In scenario A, multi-endpoint studies show ‘no adverse health effects giving concern for endocrine activity’; thus the conclusion is ‘No ED concern’. In Scenario B, targeted endpoint studies indicate ‘endocrine activity giving concern for endocrine toxicity’ but multi-endpoint studies show ‘no adverse health effects…’. The conclusion is again ‘No ED concern’. In Scenario C there is ‘sufficient evidence of endocrine disruption’ according to Weybridge. Here, multi-endpoint studies show ‘adverse effects giving concern for endocrine toxicity’ and targeted endpoint studies show ‘endocrine activity giving concern for endocrine toxicity’. Thus, the adverse health effects seen in the multi-endpoint study are supported by mechanistic evidence of an endocrine mode of action. In Scenario D, adverse effects are shown in apical studies but they are not considered as sufficient evidence of endocrine disruption because the sequence of biochemical and cellular events to support an ED-mediated mechanism cannot be defined.