Paricreas zyxwvutsrqponmlkj Vol. zyxwvutsrqponmlk 14, No. 4, pp. 355-359 zyxwvutsrqp 0 1997 Lippincott-Raven Publishers, Philadelphia Oxidative Stress Changes in L-Arginine-Induced Pancreatitis in Rats Ilona Sz. Varga, Bela Matkovics, *Laszlo Czako, Do Quy Hai, Marta Kotorman, *Tamas Takacs, and ?Maria Sasvari zyxw Biological Isotope Laboratory, “Jozsef Attila” University of Szeged, and *First Department of Medicine, “Szent-Gyorgyi Albert” Medical University, Szeged, and fCentral Research Laboratories, “Haynal Imre” Health Sciences University, Budapest, Hungary zyxw Summary: The important role of oxygen radicals in acute experimental pancreatitis was demonstrated by study of the changes in the antioxidant system in the blood, liver, kidney, and pancreas of rats after the administration of a large quantity of L-arginine (L-Arg). The changes in lipid peroxidation and in reduced and oxidized gluta- thione were followed, as well as the activities of peroxide- decomposing enzymes (glutathione peroxidase and cata- lase) and H202-producing superoxide dismutases. The re- sults demonstrated that “oxidative stress’’ develops and acute pancreatitis appears rapidly after L-Arg treatment. Oxidative stress symptoms are expressed 24 h after the final treatment. Slow restitution of the studied antioxidant system can be demonstrated as early as after 48 h. Key Words: Lipid peroxidation-Antioxidant enzymes-L- Arginine- Acute pancreatitis. A number of authors have studied the conse- quences of acute inflammation of the pancreas fol- lowing the administration of a large dose of L- arginine (L-Arg) and secretion of the enzymes produced by the acini (1,2). Besides the enzyme ac- tivities, the morphological changes induced by L-Arg administration have also been studied (3). The important role of oxygen radicals in acute pan- creatitis has been described (4-7), but nitrogen oxide (NO), the “molecule of 1992,” is also presumed to participate in the affliction of the pancreatic acini, blood vessels, and hormone-producing @ cells (8,9). The aim of the present comparative study was to establish the role of the changes in antioxidant en- zyme activities and lipid peroxidation (LP) after ad- ministration of a large dose of L-Arg to induce acute pancreatitis. Besides the plasma and the red blood cell (RBC) hemolysate, changes in the antioxidant Manuscript received May 8, 1996; revised manuscript accepted Address correspondence and reprint requests to Dr. B. October 9, 1996. Matkovics, P.O. Box 533, Szeged, H-6701, Hungary. system (AOS) in two major parenchymal organs and in the pancreas were also studied. Of the members of the AOS, the amounts of re- duced and oxidized glutathione (GSH and GSSG) and the activities of the antioxidant enzymes superox- ide dismutase (SOD; EC 1.15.1.1), catalase (C-ase; EC 1.11.1.6), and glutathione peroxidase (GP-ase; EC 1.11.1.9) were determined. MATERIALS AND METHODS The chemicals applied for enzyme measurements and other determinations were of the highest purity. They were purchased from Sigma, Merck, Boeh- ringer, Calbiochem, and Reanal. Male Wistar rats weighing 250-300 g were used in all experiments. The animals were kept at a constant room temperature of 27°C and fed with free access to water and a standard laboratory chow (LATI, GO- do114 Hungary). Pancreatitis was induced by two intraperitoneal injections of 250 mg/100 g body weight L-Arg as a 20% solution in saline, at an interval of 1 h. Control rats instead received the same amount of glycine as 355