Effects of L-Glutamine on Acetylsalycylic Acid Induced Gastric Lesions and Acid Back Diffusion in Dogs

Abstract

Abstract-Effects of L-glutamine on acetylsalicylic acid (ASA)-induced gastric mucosal lesions were studied in mongrel dogs. It was confirmed that when oral ASA at 1.0 or 2.0 g per dog is given in two divided doses, there is severe and consistent dose-dependent mucosal damage in the glandular portion of the stomach in fasted dogs. However, when L-glutamine 2.0 or 4.0 g per dog in two divided doses is given concomitantly with ASA 2.0 g per dog orally, the gastric irritation is significantly inhibited. Instillation of 20 mM of ASA in 100 mM HCl solution into the Heidenhain pouch of Beagle dogs produced a significant loss of H+ from the pouch and a gain of Na+ in the lumen com pared with ASA-free controls.When L-glutamine (100 mM) was given concomitantly with ASA (20mM) into the pouch, changes of electrolyte fluxes in response to ASA alone were significantly suppressed. However, 50 mM of L-glutamine had no appreciable effect on acid back diffusion caused by ASA 20 mM. The amino acid itself had little effect on the ionic movement in the pouch. Gross bleeding from the pouch treated with ASA was never observed with the concomitant dosing of ASA and L-glutamine 50 or 100 mM.We have already reported the marked inhibitory effect of L-glutamine on acetylsalicylic acid (ASA)-induced gastric irritation in normal, cirrhotic or pregnant rats, or in rats with a chronic gastric ulcer (1-4). It was experimentally determined that L-glutamine produces a dose-dependent inhibition of acid back diffusion in response to ASA in the rat stomach (2-5). As dogs are frequently used in the study of gastric problems related to ASA (6-9), our present work was an attempt to determine the effects of L-glutamine in this species. This report contains data on the potent effect of this amino acid in preventing the noxious effect of ASA on the gastric mucosa in normal dogs and on the acid back diffusion in response to ASA in the stomach of Heidenhain pouch Beagle dogs. MATERIALS AND METHODSASA -lesion formation: Thirty-six male mongrel dogs, weighing 8-10 kg, were deprived of food but allowed free access to water from 10:00 a.m. until the end of the experiments.