Effect of administration of diethylhexyl phthalate on the function and turnover of rat hepatic mitochondria.

Administration of the widely used plasticizer di(2-ethylhexyl)phthalate (2% w/w) in the diet to the rat caused proliferation of mitochondria in the liver. The number of mitochondria as well as the amount of protein recovered in the organellar fraction was doubled. Mitochondria isolated from the livers of treated animals showed decreased (50%) respiratory activity. The content and activity of cytochrome oxidase were also decreased. The specific incorporation of amino acids into the proteins of whole liver and of mitochondria was not increased in plasticizer-treated animals. Isolated mitochondria also did not show any difference in the rate of incorporation of amino acids into proteins. The half-lives of whole liver proteins and of mitochondria were increased in plasticizer-fed animals. The half-life of cytochrome oxidase, however, was unaffected by the treatment. The pattern of double labeling of mitochondrial proteins confirmed decreased turnover in plasticizer-treated animals.