General Guidance on Endocrine Assessment: Assays and Endpoints

33. The purpose of this section is to provide background information on the relevance of various types of data for supporting decisions about the endocrine disrupting properties of chemicals and other test materials (e.g. effluents, natural waters, contaminated foods, etc.) in humans and non-mammalian vertebrates. Interpretation of results from some invertebrate test guidelines is also included, but due to the rather poor current understanding of endocrinology in most invertebrates, and the lack of diagnostic screening endpoints with these taxonomic groups (e.g. OECD [2010c]), guidance cannot yet be given for many of these assays. Nevertheless, non-OECD test assays, including those utilising invertebrate species, may provide information that can be used in a weight of evidence (WOE) approach. Furthermore, the document only deals with estrogen-, androgenand thyroidmediated endocrine disruption, and with interference with steroidogenesis (although some guidance is also provided for evaluation of juvenile hormone, ecdysteroid and retinoid activity). It does not cover other possible types of endocrine disruption, such as effects on the hypothalamus-pituitary-adrenal axis or other receptor pathways. Some advice on the endocrine control of neural development is provided, but this is only rudimentary. The section is organised according to the OECD Conceptual Framework (CF) (see Section A.2), as updated in 2017 with tests which were unavailable or not included when it was first proposed.