Role of Pepsin in Experimental Production of Gastric Ulcer in the Rat.

Abstract

The rôle of gastric juice in the etiology of gastric and duodenal ulcer has been stressed. The hydrochloric acid has received the major portion of attention. This investigation attempts to evaluate the relative importance of pepsin in the experimental production of gastric ulcer in the albino rat. Buchner, Siebert and Malloy reported that subcutaneous injections of histamine into fasting rats produced ulcers of the prostomach. These authors, as well as Burkle-de la Camp contended that the resultant increase of both hydrochloric acid and pepsin were responsible for the observed ulcers. It occurred to us that a more direct approach to this problem could be made with controlled feeding experiments, employing mixtures of pepsin and hydrochloric acid and hydrochloric acid alone. In such manner, we felt that the relative importance of these factors could be evaluated. A total of 58 rats of the original Wistar strain, averaging in age 4 months, were fed the Steenbock-Bills stock diet. Fresh lettuce or sliced carrots were added on feeding days. Fluids were supplied by means of stoppered flasks, with glass tube outlets, attached to the cages. The rats were then able to partake of these solutions ad lib. The first group (1) received a 20% (by weight) mixture of granular pepsin (1:10,000 Parke, Davis and Co.) in 0.3% solution of hydrochloric acid. The second group (2) received a 0.3% solution of hydrochloric acid alone. These solutions were freshly prepared every other day. One-half of each group (A) were fasted for 2 days and fed on the 3rd day; the control half of each group (B) had access to food at all times. The third group (3) received a 20% (by weight) mixture of inactivated pepsin (by heat) in 0.3% solution of hydrochloric acid, being fasted for 2 days and fed on the 3rd day.