Short term exposure to di-n-butyl phthalate (DBP) disrupts ovarian function in young CD-1 mice

• A 10-day exposure to DBP disrupted reproductive processes in CD-1 mice.
• DBP exposure resulted in decreased circulating 17β-estradiol.
• Antral follicle numbers and apoptosis gene expression were altered at low doses.
• Estrous cyclicity and corpora lutea counts were altered at a high dose.
• DBP exposure resulted in altered steroidogenesis gene expression.

Di-n-butyl phthalate (DBP) is present in many beauty and medical products. Human exposure estimates range from 0.007–0.01 mg/kg/day in the general population and up to 0.233 mg/kg/day in patients taking DBP-coated medications. Levels of phthalates tend to be higher in women, thus, evaluating ovarian effects of DBP exposure is of great importance. Mice were given corn oil (vehicle) or DBP at 0.01, 0.1, and 1000 mg/kg/day (high dose) for 10 days to test whether DBP causes ovarian toxicity. Estrous cyclicity, steroidogenesis, ovarian morphology, and apoptosis and steroidogenesis gene expression were evaluated. DBP exposure decreased serum E2 at all doses, while 0.1DBP increased FSH, decreased antral follicle numbers, and increased mRNA encoding pro-apoptotic genes (Bax, Bad, Bid). Interestingly, mRNAs encoding the steroidogenic enzymes Hsd17b1, Cyp17a1 and Cyp19a1 were increased in all DBP-treated groups. These novel findings show that DBP can disrupt ovarian function in mice at doses relevant to humans.