Estrogenic Action by an Impurity in Flame Retardant Formulations Impairs the Development of Female Reproductive Functions

Developmental exposure to environmental chemicals with estrogen-like activity has been known to permanently impair women’s health. In this study, we examined whether tris(2,6-dimethylphenyl) phosphate (TDMPP), an impurity in flame retardant that is not classified as endocrine disruptor at present, impairs sexual differentiation of the brain in mice. Either TDMPP, 17beta-estradiol (E2) as a positive control, or sesame oil as a negative control was administered during late pregnancy and early postnatal period and female reproductive functions of offspring were elucidated. Precocious puberty, irregular estrous cycles, and lowered lordosis response were found in TDMPP-treated group as well as E2-treated group. We also detected masculinization of sexual dimorphic nuclei in the hypothalamus of female mice after TDMPP treatment. Taken together, our empirical evidence suggests that the developmental exposure to TDMPP by using products containing TDMPP might be a potential risk to impair female reproductive functions at later life stages.