A whole body autoradiographic study on the distribution of 14C-labelled di-(2-ethylhexyl)phthalate in mice

Di-(2-ethylhexyl)phthalate (DEHP), a plasticizer used for polyvinylchloride polymers, has been reported to leach from blood transfusion bags and the plastic material in hemodialysis units into the blood. Phthalate esters are known to be hepatotoxic and teratogenic in experimental animals. Reports on the distribution and metabolism of DEHP indicate that the compound in largely excreted from the body within a few days. In the present investigation the distribution and tissue retention after administration of [14C]DEHP (carbonyl-14C or 2-ethylhexyl-1-14c) was studied in pregnant and non-pregnant mice with whole body autoradiography. Initially a high activity was observed in the brown fat, liver, gall bladder, intestinal contents, kidney and urinary bladder. Pretreatment with DEHP, phenobarbital sodium or 3-methylcholanthrene caused a relative increase of the activity in the brown fat, indicating that induced metabolic conversion of DEHP leads to an increased deposition of radioactivity in brown fat. After administration of DEHP (carbonyl-14C), but not DEHP (2-ethylhexyl-1-14C),marked retention was observed in the skin, cartilage and tendons. The mechanism responsible for the slow accumulation in these connective tissues is not known. In the early embryo a high concentration was observed in the neuroepithelium. This pronounced uptake may be correlated to the DEHP-induced malformations exencephaly and spina bifida observed in mice.