Effects of dietary di(2-ethylhexyl)phthalate on the structure and function of rat hepatocytes

The effect of the plasticizer di(2-ethylhexyl)phthalate on the intracellular membranes of hepatocytes was investigated. Supplementation of the diet with 2% plasticizer resulted in the appearance of a large number of peroxisomes, and the number of mitochondria was also greatly increased. No significant change in the amount or appearance of the endoplasmic reticulum was detected. The oxidation of palmitoyl-CoA in peroxisomes and the activities of carnitine-acyltransferases are increased to a great extent in both mitochondria and peroxisomes. Intact respiratory control and oxidative phosphorylation indicated that mitochondrial integrity was maintained during the induction. In microsomes, cytochrome P-450 and NADPH-cytochrome c reductase are elevated. The increased incorporation of glycerol into phospholipids indicated an increased rate of synthesis. The induction of peroxisomal and mitochondrial membranes and enzymes, but not of the membranes of the endoplasmic reticulum, by phthalate esters is an unusual and valuable induction pattern not seen with other inducers.