Differing effects of ethanol on in vitro stimulated pancreatic enzyme secretion in ethanol-fed and control rats

Abstract

The single most important risk factor for chronic and acute pancreatitis is the abuse of ethanol, which, theoretically, could affect the pancreas by interacting either with some of its cell receptors or with any of its intracellular signal transduction mechanisms. Therefore, we determined in isolated pancreatic acini from 3 month ethanol-fed rats and controls the dose-response effects of secretagogues on enzyme secretion, both in the presence and absence of ethanol in the incubation medium. In ethanol-fed rats, pancreatic amylase activity was decreased by 40%, compared to controls (with identical carbohydrates intakes), whereas lipase and trypsinogen activities were unaffected. With no ethanol in the incubation medium, basal enzyme releases and enzyme dose-response curves to CCK-8, VIP, secretin, bombesin, and bethanechol were essentially unchanged in ethanol-fed rats compared to controls. In contrast, with 0.1 M ethanol present in the medium, enzyme responses to VIP, secretin, and CCK-8 were inhibited and that to CCK-8 also shifted to the right in ethanol-fed rats compared to controls. Hence, if rechallenged to ethanol, acini from ethanol-fed rats show inhibited secretions, in response to two secretagogues acting through the release of cyclic AMP, and an inhibited and right-shifted secretory response to CCK.