The effect of chronic ethanol consumption on labeled glycoprotein secretion and galactosyltransferase activity has been analyzed in cis- and trans-Golgi apparatus fractions isolated from rat liver. Rats were injected intraperitoneally with 3H-leucine, after different chase periods (30, 60, 180 min), and the radioactivity of the different subcellular fractions as well as of the isolated Golgi apparatus was measured. Chronic alcohol treatment induces an increase in liver weight as well as an enhancement of total liver protein. Ethanol treatment produces a significant accumulation of labeled proteins in isolated Golgi apparatus fractions after a 60- and 180-min chase. An accumulation of labeled proteins in the cytosolic fraction was observed only after 180 min. The alcohol treatment also induces a significant decrease in the activity of galactosyltransferase in both liver homogenate and Golgi apparatus fractions. These results suggest that an impairment of Golgi apparatus functions, including glycosylation and glycoprotein trafficking, could be one of the mechanisms involved in the accumulation of hepatic protein and thus in the pathogenesis of alcohol-induced injury in the liver of chronic ethanol-consuming animals.