Regulatory needs and activities to address the retinoid system in the context of endocrine disruption: The European viewpoint.

Endocrine disruption continues to be a matter of high concern, and a subject of intensive activities at the public, political, regulatory and academic levels. Currently, available regulatory test guidelines (TGs) relevant to the identification of endocrine disrupters are largely limited to estrogen, androgen, thyroid and steroidogenesis (EATS) pathways. Thus, there is an increasing interest and need to develop test methods, biomarkers, and Adverse Outcome Pathways (AOPs), for identification and evaluation of endocrine disrupters in addition to the EATS pathways. An activity focusing on the retinoid system has been jointly initiated by the Swedish Chemicals Agency and the European Commission. The retinoid system is involved in fundamental life processes and has been described, in previous work at the OECD, as a system susceptible to environmental endocrine disruption, the disruption of which could contribute to the increasing incidence of certain disorders in humans and wildlife populations.