EXPERIMENTAL STUDY OF THE ROLE OF THE PITUITARY-ADRENAL SYSTEM IN DEVELOPMENT OF STRESS ULCER INDUCED BY WATER IMMERSION

Abstract

The role of the pituitary-adrenal system in the development of stress ulcer induced by water immersion was evaluated in hypophysectomized rats. Changes with time after stress loading were studied with respect to the Ulcer Index (U.I.) along with the gastric pH and serum gastrin level as aggressive factors and the amount of gastric mucus glycoprotein (hexose) and gastric mucosal blood flow as defensive factors. In controls, the gastric pH decreased immediately after the stress loading, and the U.I. and gastrin level began to increase after 4 hours. The amount of hexose significantly decreased with time, and gastric mucosal blood flow decreased by about 50% in the eraly stage. In the hypophysectomized rats, increases in the U.I. was inhibited, but the effects of stress on the gastric pH, gastrin level, amount of hexose, and gastric mucosal blood flow were negligible. These results show that the pituitary-adrenal system plays an important role in the development of stress ulcer.