GASTRIC BICARBONATE SECRETION, ACID-SECRETION, AND MUCOSAL BLOOD-FLOW DURING INFLUENCE OF PENTAGASTRIN AND OMEPRAZOLE IN THE CAT

In this study secretion of bicarbonate and acid and mucosal blood flow were determined simultaneously in cats. The gastric lumen of anesthetized cats was continuously perfused with isotonic saline. Secretion of HCO-3 and H+ was calculated from continuous measurements of pH and Pco2 in the perfusate. Mucosal blood was measured by means of radiolabeled microspheres. Under resting acid secretory conditions, bicarbonate secretion into the gastric lumen averaged 1.0-mu-mol/min. Somewhat surprising, both omeprazole (4 mg/kg as bolus) and pentagastrin (16-mu-g/kg.h intravenously) significantly reduced the HCO3- secretion. Omeprazole did not influence mucosal blood flow, whereas corpus mucosal blood flow increased during pentagastrin stimulation. Under resting acid secretory conditions and during omeprazole treatment there was a close linear relationship between acid and bicarbonate secretion. No such relationship was found during pentagastrin stimulation of the mucosa. No consistent relationship was obtained between blood flow and bicarbonate secretion in normal gastric mucosa.