Effects of prolonged administration of phthalate ester on the liver.

Di(2-ethylhexyl)phthalate (DEHP) was administered to male rats in the diet at concentrations of 2.0, 0.2, and 0.02% for up to 102 weeks. Low doses resulted in moderate increases in certain hepatic enzymes during the initial phase of exposure and in a continuous increase in the activities of these same enzymes throughout the treatment period. An increased level of dolichol and decreased concentration of dolichyl-P were observed. Furthermore, the rate of protein glycosylation diminished. Liver biopsies from patients subjected to hemodialysis demonstrated an increased number of peroxisomes. Phthalate ester seems to interfere with protein turnover, so that the half-life of total mitochondrial and microsomal protein is considerably increased.