The in vitro response (defined as changes in growth rate, cellular protein content, and albumin secretion) of liver epithelial cells to the putative hepatotoxins ethanol and acetaldehyde were evaluated using the well-characterized 32IIIA 6/2d rat liver tumor clonal cell line. Exposure of hepatic tumor cells to ethanol (50-100 mM) for a period of 3 days reduced final population density (apparently due to a drug-induced increase in mean cell cycle transit time), reduced secretion of albumin, and increased the mean cellular protein content. Since these ethanol-associated effects were also observed in cells cultured in growth medium containing acetaldehyde (0.1 mM), and were inhibited by simultaneous addition of pyrazole, the changes in the parameters measured in this study appear to be induced by products of ethanol metabolism. These data complement recent in vivo studies implicating acetaldehyde as an inhibitor of hepatocyte secretory function. The 32IIIA 6/2d liver cell system, thus, responds to certain hepatotoxic compounds in a manner analogous to the in vivo organ and may facilitate future analysis of molecular mechanisms underlying alcohol-induced liver disease under defined culture conditions.