Peroxisome proliferation in cultured rat hepatocytes produced by clofibrate and phthalate ester metabolites.

Adult rat hepatocytes cultured for 48 h in the presence of 0.2 mM clofibrate, mono-(2-ethylhexyl)-phthalate (MEHP) or 2-ethylhexanol (2-EHA) contained increased numbers of peroxisomes. In keeping with the effects of these compounds in vivo, the peroxisome proliferation was associated with marked increases (up to 15-fold) in the activity of carnitine acetyltransferase. No such effects were produced by n-hexanol or two microsomal enzyme inducers, phenobarbital and 1,2-benzanthracene. These results suggest that cultured hepatocytes may provide a useful model system for studying chemically induced peroxisome proliferation.