Gastroenterology

Gastroenterology

Volume 122, Issue 1, January 2002, Pages 106-118
Gastroenterology

Basic Research
Ethanol metabolism and transcription factor activation in pancreatic acinar cells in rats,**

https://doi.org/10.1053/gast.2002.30302Get rights and content

Abstract

Background & Aims: Ethanol metabolism by pancreatic acinar cells and the role of its metabolites in ethanol toxicity to the pancreas remain largely unknown. Here, we characterize ethanol metabolism in pancreatic acinar cells and determine the effects of ethanol metabolites on nuclear factor κB (NF-κB) and activator protein (AP)-1, transcription factors that are activated in pancreatitis and mediate expression of inflammatory molecules critical for this disease. Methods: We measured activities of fatty acid ethyl ester (FAEE) synthase and alcohol dehydrogenase (ADH), as well as accumulation of ethanol metabolites. We measured the effects of ethanol and its metabolites on NF-κB and AP-1 activation by using a gel shift assay. Results: Pancreas metabolizes ethanol via both oxidative and nonoxidative pathways. Acinar cells are the main source of ethanol metabolism in the pancreas. Compared with the liver, FAEE synthase activity in the pancreas is greater, whereas that of ADH is much less. FAEEs activated NF-κB and AP-1, whereas acetaldehyde inhibited NF-κB activation. Ethanol decreased NF-κB binding activity in acinar cells, which was potentiated by cyanamide. Conclusion: Oxidative and nonoxidative ethanol metabolites regulate transcription factors differently in pancreatic acinar cells. Ethanol may regulate NF-κB and AP-1 positively or negatively, depending on which metabolic pathway's effect predominates. These regulatory mechanisms may play a role in ethanol toxicity to the pancreas.

GASTROENTEROLOGY 2002;122:106-118

Section snippets

Isolation of pancreatic acini

Pancreas was dissected from Sprague-Dawley rats (100-150 g), and dispersed pancreatic acini were isolated by a standard collagenase digestion method as described previously.9, 10, 12

Enzyme assays

Activities of the enzymes, FAEE synthase and ADH, were measured in cell or tissue lysates. To measure FAEE activity, tissue or isolated pancreatic acini were homogenized in 10 mmol/L Tris-HCl buffer (pH 8.0) containing 1 mmol/L phenylmethylsulfonyl fluoride, 1 mmol/L β-mercaptoethanol, and a protease-inhibitor

Characteristics of ethanol-metabolizing enzymes

The results in Figure 1 compare activities of ethanol-metabolizing enzymes in isolated pancreatic acini and pancreatic and liver tissue of normal rat.

. Activities of FAEE synthase and ADH in rat pancreatic and liver tissue, and isolated pancreatic acini. (A) FAEE synthase activities were measured in cell or tissue lysates incubated for 1 hour with 0.4 mmol/L [14C] oleate and ethanol at indicated concentrations. FAEE accumulation was measured as described in the Materials and Methods section.

Discussion

The results of this study show that pancreatic acinar cells are the main source of ethanol metabolism in the pancreas because isolated acinar cells and pancreatic tissue show the same levels of activities of ethanol-metabolizing enzymes. In the pancreas, accumulation of the oxidative metabolite, acetate, is greater than of the nonoxidative product, FAEE. The activity of ADH is also greater than that of FAEE synthase. Of note, the values for both the oxidative and nonoxidative pathways represent

Acknowledgements

The authors thank David T. Kira for help with nuclear extract preparations, and Yoon Jung for help in preparing this article.

References (55)

  • J Werner et al.

    Pancreatic injury in rats induced by fatty acid ethyl ester, a nonoxidative metabolite of alcohol

    Gastroenterology

    (1997)
  • MD Boleda et al.

    Role of extrahepatic alcohol dehydrogenase in rat ethanol metabolism

    Arch Biochem Biophys

    (1989)
  • PS Haber et al.

    Metabolism of alcohol by human gastric cells: relation to first-pass metabolism

    Gastroenterology

    (1996)
  • H Ohata et al.

    Determination of acetaldehyde in biological samples by gas chromatography with electron-capture detection

    J Chromatogr B Biomed Sci Appl

    (1997)
  • M Krieger et al.

    Replacement of endogenous cholesteryl esters of low density lipoprotein with exogenous cholesteryl linoleate. Reconstitution of a biologically active lipoprotein particle

    J Biol Chem

    (1978)
  • ZM Szczepiorkowski et al.

    Fatty acid ethyl esters decrease human hepatoblastoma cell proliferation and protein synthesis

    Gastroenterology

    (1995)
  • J Teruya et al.

    Mode of transport of fatty acid to endothelial cells influences intracellular fatty acid metabolism

    J Lipid Res

    (1995)
  • T Miyake et al.

    Quantitative analysis of acetaldehyde in whole blood from human and various animals by gas chromatography

    J Chromatogr B Biomed Sci Appl

    (1998)
  • K Jokelainen et al.

    Acetaldehyde inhibits NF-kappaB activation through IkappaB preservation in rat Kupffer cells

    Biochem Biophys Res Commun

    (1998)
  • S Schenker et al.

    Alcohol and the pancreas

    Recent Dev Alcohol

    (1998)
  • AB Lowenfels et al.

    Prognosis of chronic pancreatitis: an international multicenter study

    Am J Gastroenterol

    (1994)
  • M Bhatia et al.

    Inflammatory mediators in acute pancreatitis

    J Pathol

    (2000)
  • J Norman et al.

    Acute pancreatitis induces intrapancreatic tumor necrosis factor gene expression

    Arch Surg

    (1995)
  • J Norman et al.

    Decreased mortality of severe acute pancreatitis after proximal cytokine blockade

    Ann Surg

    (1995)
  • AS Gukovskaya et al.

    Pancreatic acinar cells produce, release and respond to tumor necrosis factor-alpha: role in regulating cell death and pancreatitis

    J Clin Invest

    (1997)
  • I Gukovsky et al.

    Early NF-kappaB activation is associated with hormone-induced pancreatitis

    Am J Physiol

    (1998)
  • V Zaninovic et al.

    Cerulein upregulates ICAM-1 in pancreatic acinar cells, which mediates neutrophil adhesion to these cells

    Am J Physiol

    (2000)
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      FAEEs can be detected in plasma and other tissues after alcohol consumption [7,9]. On the other hand, pancreatic alcohol dehydrogenase (ADH) and cytochrome P450E1 (CYP2E1) activities involved in the canonical oxidative pathway of EtOH metabolism are relatively low or negligible [5]. Inhibition of hepatic ADH1 (a major enzyme involved in EtOH oxidation) leads to increased biosynthesis of FAEEs in the pancreas and toxicity to the pancreatic acinar cells [2,5,6,8,10–15].

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    Address requests for reprints to: Anna S. Gukovskaya, Ph.D., Veterans Affairs Greater Los Angeles Healthcare System, Building 258, Room 340, 11301 Wilshire Boulevard, Los Angeles, California 90073. e-mail: [email protected]; fax: (310) 268-4578.

    **

    Supported by the Research Center for Alcoholic Liver and Pancreatic Diseases grant (P50-A11999) from the National Institute on Alcohol Abuse and Alcoholism. The gas chromatography–mass spectrometry measurements were supported by a Veterans Administration Merit Review Award (to L.D.F.).

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