Assessment strategies of endocrine disrupters under regulations of the Ministry of the Environment of Japan

Abstract

Abstract Endocrine-disrupting effects of chemicals on human health and wildlife have been widely regarded as an important issue for their potential transgenerational effects. The Ministry of the Environment of Japan (MOE) published its fourth program on endocrine disrupting effects of chemical substances “EXTEND 2016” of which the basic concepts and the framework were inherited from the preceding program “EXTEND 2010,” in June 2016. The EXTEND 2016 Program, which consists of Tier-1 screening to evaluate endocrine disrupting potency and Tier-2 testing to assess adverse endocrine disrupting effects on animals, has been progressing on the implementation of testing and assessment strategies, focusing on effects on reproduction (estrogen and androgen related), development (thyroid hormone related), and growth (juvenile and ecdysone hormones related). Regarding effects on reproduction, applying an in vitro reporter gene transcriptional assay using estrogen and androgen receptors, for example, the estrogen receptor α and the androgen receptor β of Japanese medaka (Oryzias latipes), and an in vivo Fish Short-Term Reproduction Assay established as Organization for Economic Cooperation and Development (OECD) Test Guideline no. 229 (OECD TG229) with Japanese medaka are used in the Tier-1 screening. In the EXTEND 2016 Program, the Medaka Extended One Generation Reproduction Test (MEOGRT), which has been adopted as OECD TG240, is conducted for candidate chemicals in which effects on fish reproduction were suspected based on the results of the Tier-1 screening evaluation. The current progress of the activity of the EXTEND2016 and future perspectives are addressed.