The effect of chronic ethanol consumption on salivary gland morphology and function in the rat

Chronic ethanol consumption in rats resulted in a striking fat accumulation in the acinar cells of the parotid gland demonstrated by light microscopy. In addition, a significant decrease in parotid wet weight (p greater than 0.02) and in protein content of the gland (p greater than 0.02) was observed following alcohol feeding. Wet weight, protein content, and morphology of the submaxillar gland were not affected by ethanol feeding. Alcohol metabolism, similar to that found in the pancreas, via a cytosolic alcohol dehydrogenase could be demonstrated in both the parotid and the submaxillar gland. However, the activity of this enzyme was not affected by chronic ethanol ingestion. Subsequently, chronic ethanol consumption significantly decreased salivary flow rate stimulated by pilocarpine hydrochloride (p greater than 0.02), salivary alpha-amylase activity (p greater than 0.02), and salivary sodium concentration (p greater than 0.01), whereas potassium concentration of the saliva was increased (p greater than 0.05). In contrast salivary total protein concentration was not affected by alcohol ingestion. The changes of salivary electrolyte composition observed after chronic ethanol feeding could be due to an altered aldosterone metabolism or to a change in aldosterone receptors of the parotid gland caused by ethanol administration. The reduced salivary flow could play a role in the pathogenesis of oropharyngeal cancer in the alcoholic.