Teratogenic potential of di- and mono-(2-ethylhexyl)phthalate in mice.

Fetotoxicity of di-(2-ethylhexyl)phthalate (DEHP) and its metabolite, mono-(2-ethyhexyl)phthalate (MEHP) was studied in pregnant mice (ddY-Slc female X CBA male). With the oral administration of DEHP 5.0 or 10.0 ml/kg representing 1/6 or 1/3 of the acute LD50 dose on day 7 of gestation there were no live fetuses. When DEHP 10.0 ml/kg was given on days 9 or 10 of gestation, however, the rates of live fetuses were 91.7% and 95.4% respectively. Gross and skeletal abnormalities in the live fetuses occurred with 2.5 or 7.5 ml/kg of DEHP given orally on days 7 or 8 of gestation respectively. Similar toxic effects were observed with the administration of MEHP. The oral administration of 0.5 or 1.0 mg/kg on day 8 of gestation resulted in 11-19% and 100% of gross and skeltal abnormalities, respectively. The gross abnormalities included exencephaly, open eyelid and club foot. Skeltal abnormalities occurred in the skull, cervical and/or thoracic bones. Thus both DEHP and MEHP exert similar effects on the mouse fetus and the lethal and/or teratogenic effects of DEHP are probably due to its metabolite, MEHP.