Beer but not wine, hard liquors, or pure ethanol stimulates amylase secretion of rat pancreatic acinar cells in vitro

Release of Cholecystokinin from Rat Intestinal Mucosal Cells and the Enteroendocrine Cell Line STC-1 in Response to Maleic and Succinic Acid, Fermentation Products of Alcoholic Beverages

Alcoholic beverages stimulate pancreatic enzyme secretions by inducing cholecystokinin (CCK) release. CCK is the major stimulatory hormone of pancreatic exocrine secretions, secreted from enteroendocrine I-cells of the intestine. Fermentation products of alcoholic beverages, such as maleic and succinic acids, influence gastric acid secretions. We hypothesize that maleic and succinic acids stimulate pancreatic exocrine secretions during beer and wine ingestion by increasing CCK secretions. Therefore, the effects of maleic and succinic acids on CCK release were studied in duodenal mucosal cells and the enteroendocrine cell line STC-1. Mucosal cells were perfused for 30 min with 5 min sampling intervals, STC-1 cells were studied under static incubation for 15 min, and supernatants were collected for CCK measurements. Succinate and maleate-induced CCK release were investigated. Succinate and maleate doses dependently stimulated CCK secretions from mucosal cells and STC-1 cells. Diltiazem, a calcium channel blocker, significantly inhibited succinate and maleate-induced CCK secretions from mucosal cells and STC-1 cells. Maleate and succinate did not show cytotoxicity in STC-1 cells. Our results indicate that succinate and maleate are novel CCK-releasing factors in fermented alcoholic beverages and could contribute to pancreatic exocrine secretions and their pathophysiology.

Identification of beer bitter acids regulating mechanisms of gastric acid secretion

Beer, one of the most consumed beverages worldwide, has been shown to stimulate gastric acid secretion. Although organic acids, formed by fermentation of glucose, are known to be stimulants of gastric acid secretion, very little is known about the effects of different types of beer or the active constituents thereof. In the present study, we compared the effects of different beers on mechanisms of gastric acid secretion. To investigate compound-specific effects on mechanisms of gastric acid secretion, organic acids and bitter compounds were quantified by HPLC-DAD and UPLC-MS/MS and tested in human gastric cancer cells (HGT-1) by means of a pH-sensitive fluorescent dye which determines the intracellular pH as an indicator of proton secretion. The expression of relevant genes, coding the H(+)/K(+)-ATPase, ATP4A, the histamine receptor, HRH2, the acetylcholine receptor, CHRM3, and the somatostatin receptor, SSTR2, was determined by qPCR. Ethanol and the organic acids succinic acid, malic acid, and citric acid were demonstrated to contribute to some extent to the effect of beer. The bitter acids comprising α-, β-, and iso-α-acids were identified as potential key components promoting gastric acid secretion and up-regulation of CHRM3 gene expression by a maximum factor of 2.01 compared to that of untreated control cells with a correlation to their respective bitterness.

Pancreas - non-alcoholic constituents and their effects

Alcoholic beverages contain numerous non-alcoholic compounds that could have beneficial or pathological effects. For example, up to now in beer more than 2,000 and in wine more than 1,000 organic and inorganic constituents have been identified. Whereas the role of alcohol (ethanol) in the development of pancreatic diseases - in particular acute and chronic pancreatitis - has been intensively investigated, only little is known about the effects of non-alcoholic compounds in this context. Some of the non-alcoholic constituents have been shown to be biologically active, although discussions of the results in appropriate publications were often not performed with regard to their consumption as a mixture in alcoholic beverages. In this article we provide an overview about the newest data concerning the effect of non-alcoholic constituents of alcoholic beverages, especially of beer, on pancreatic secretion and their possible role in alcoholic pancreatitis. The data indicate that non-alcoholic constituents of beer stimulate pancreatic enzyme secretion in humans and rats, at least in part, by direct action on pancreatic acinar cells. However, there is accumulating evidence that non-alcoholic compounds of alcoholic beverages exert different effects on the pancreas. The effects and mechanisms of most single compounds and their combinations are still unknown and thus caution is required in attempting to draw firm conclusions on the effect of non-alcoholic compounds of alcoholic beverages on defining alcoholic etiology of pancreatitis.

Beer and its non-alcoholic compounds: role in pancreatic exocrine secretion, alcoholic pancreatitis and pancreatic carcinoma

In this article we provide an overview of the newest data concerning the effect of non-alcoholic constituents of alcoholic beverages, especially of beer, on pancreatic secretion, and their possible role in alcoholic pancreatitis and pancreatic carcinoma. The data indicate that non-alcoholic constituents of beer stimulate pancreatic enzyme secretion in humans and rats, at least in part, by direct action on pancreatic acinar cells. Some non-alcoholic compounds of beer, such as quercetin, resveratrol, ellagic acid or catechins, have been shown to be protective against experimentally induced pancreatitis by inhibiting pancreatic secretion, stellate cell activation or by reducing oxidative stress. Quercetin, ellagic acid and resveratrol also show anti-carcinogenic potential in vitro and in vivo. However, beer contains many more non-alcoholic ingredients. Their relevance in beer-induced functional alterations of pancreatic cells leading to pancreatitis and pancreatic cancer in humans needs to be further evaluated.

Beer-induced pancreatic enzyme secretion: characterization of some signaling pathways and of the responsible nonalcoholic compounds

BACKGROUND

Various alcoholic beverages have different effects on pancreatic enzyme secretion in vivo and in vitro. Recently we demonstrated that beer dose-dependently induces amylase release of rat pancreatic acinar cells, whereas pure ethanol and other alcoholic beverages have no effect. The aims of this study were to: (1) investigate the involved signaling pathways in the beer-induced enzyme secretion of rat pancreatic acinar cells and (2) characterize the responsible nonalcoholic compounds from beer.

METHODS

Rat pancreatic AR4-2J cells were differentiated by dexamethasone treatment for 72 hours. After incubation of cells with 1 to 10% (v/v) beer (containing 4.7% v/v ethanol) in the absence or presence of the maximal effective concentration of cholecystokinin (CCK) (100 nM) for 60 minutes, protein secretion was measured using amylase activity assay. To study the involved signaling pathways, cells were pretreated with selective inhibitors or the fluorescent dye Fura2/AM for 15 and 30 minutes, respectively. To characterize the responsible compounds, beer was distilled, lyophilized, dialyzed, or treated with proteases prior stimulation of the cells. Extract of barley was prepared by boiling the crop and subsequent filtration.

RESULTS

Stimulation with 5% and 10% beer (v/v) significantly (p < 0.001) increased maximally CCK-induced amylase by 55 +/- 25% and 56 +/- 37%, respectively. By using selective antagonists, we found that inhibition of phospholipase C (PLC) and inositol 1,4,5-trisphosphate-receptor binding reduced beer-induced amylase release, whereas inhibition of protein kinase C, adenylate cyclase, and protein kinase A had no significant effect. Using the fluorescent Ca(2+) indicator Fura-2/AM revealed that beer induces an increase of cytosolic free Ca(2+) concentration. Stimulation of AR4-2J cells with preproducts of beer and fermented glucose indicated that the stimulatory substances from beer derived from barley and are not produced during alcoholic fermentation. Furthermore, the stimulants from beer are thermostable, nonvolatile substances with a molecular weight higher than 15 kDa.

CONCLUSIONS

Beer-induced enzyme secretion of AR4-2J cells is, at least in part, mediated by the activation of PLC and subsequent Ca(2+) release from internal stores. However, the additive effect of beer on CCK-induced amylase release suggests that additional signaling pathways are involved. The yet unknown stimulants of pancreatic enzyme secretion originate from barley and their stimulatory potential is maintained during the process of malting and brewing.