Production of Pylorospasm and Prepyloric Ulcers in Rats

Abstract

We reported that ulceration of the prostomach of rats following protein restriction was due to the action of the acid gastric juice. 1 An investigation was therefore undertaken to determine whether the gastric acidity was increased by protein restriction. To estimate the acidity, from 15 to 100 pieces of iron, steel or aluminum were given daily to 10 rats, by a method described elsewhere, 2 and the degree of erosion or the percentage of weight lost in passage through the digestive tract was noted. Tests were made for periods of from 47 to over 100 days during which chiefly the protein content of the diets was changed from time to time. Data thus obtained 3 were complicated by factors that tended to obscure evidence of changes in gastric acidity but the net impression was that ulceration of the prostomach occurred as a result of protein restriction without a marked increase in the gastric acidity of any of these rats.

A more definite and striking consequence of protein restriction in 7 of the 10 rats was the development of a gastric retention and a correspondingly increased erosion of test material, in some instances more than 10 times the normal. The retention was apparently due to the onset of pylorospasm. As the test material consisted mainly of pieces of iron and aluminum wire, the immediate inference might be that the pieces of metal irritated the pyloric region and spastic contractions were the consequence. But this would not explain why, in spite of continuing to give the same kinds and amounts of metal daily, it repeatedly proved possible to clear up growing gastric retentions by simply changing the diet from low to high protein. Moreover, pylorospasm and gastric retention were not observed to be promoted when rats were kept on diets consisting mainly of bran 1 nor when they were given larger amounts of rougher pieces of metal during longer periods in an earlier study but during which only adequate diets were used. 2