USE OF CULTURED-HEPATOCYTES AS AN ALTERNATIVE METHOD TO STUDY THE EFFECTS OF PCBS ON LIVING ORGANISMS

In order to study the mechanism of action of polychlorinated biphenyls (PCBs) several parameters have been monitored in cultured foetal rat and quail hepatocytes. At low concentrations, the PCB mixture tested ( Aroclor 1254) did not affect the biological and morphological paramete rs studied. Above 170 mug/ml, Aroclor induced cytotoxic effects and mo rphological damage, similar to those that have been observed in vivo, in both animal species (i.e. modification of the endoplasmic reticulum structure, appearance of cytoplasmic vacuoles, alteration of the mito chondrial cisternae). Concentrations as low as 10 mum (3 ppm) induced cytochrome P450IA1-dependent activities (ethoxyresorufin-O-deethylase, ethoxycoumarin-O-deethylase) in rat hepatocytes. In quail hepatocytes , a very significant induction was observed at concentrations as low a s 1 muM. This induction was dependent on both dose and duration of exp osure. Testosterone metabolism was not affected by the PCB treatment. These in vitro models are helpful alternatives to in vivo systems for the study of the mechanism of action of PCBs on hepatocytes.