Effect of chronic ethanol feeding on pancreatic enzyme secretion in rats in vitro.

The effect of long-term ethanol intake on pancreatic digestive enzyme secretion was determined in Sprague-Dawley rats. Weight-matched triplets were fed Lieber-DeCarli diet containing 5% w/v concentration of ethanol, isocaloric amounts of Lieber-DeCarli diet, or rat chow ad libitum for 6, 12, and 18 months. Basal and bethanechol-stimulated secretion of amylase, lipase, trypsinogen, chymotrypsinogen, and pancreatic secretory trypsin inhibitor (PSTI) was determined. In the ethanol-fed group, basal secretion of trypsinogen and chymotrypsinogen was increased at 6, 12, and 18 months. In addition, basal secretion of amylase and lipase was increased and that of PSTI was decreased at 12 and 18 months. Secretion of PSTI was stimulated by bethanechol (10(-4)M), whereas the secretion of digestive enzymes was not stimulated in the ethanol-fed versus two control groups. At 12 months the dose-response curve of amylase and lipase secretion was shifted upwards in the ethanol-fed group with increase in ED50. These data are suggestive of membrane perturbations leading to increased basal secretion and a subsensitivity of the cholinergic receptors in the ethanol-fed group. Increased basal secretion of proteases in the presence of diminished trypsin inhibitor indicates that premature activation of proenzymes could occur resulting in pancreatitis.