A L PRODUCTION OF PYLOROSPASM AND GASTRIC RETENTION IN RATS BY FREDERICK HOELZEL ANn

Pylorospasm and gastric retention in man have been regarded as important factors in the genesis of peptic ulcers (1) but the factors controlling pyloric function and gastric evacuation have continued to remain more or less obscure (2). Attempts to produce pylorospasm in dogs do not seem to have met with success (lb). Our own study of the subject began in an at tempt to determine whether the gastric acidity of rats was increased by diets low in protein, as had been found to be the case in man (3). The methods used to determine gastric acidity in man could not well be applied to rats, but it seemed possible that the degree of erosion of suitable pieces of metal, introduced into the stomach of rats, might serve as an index of gastric acidity. Such a method was already used by Spallanzani when he gave calcareous materials (pieces of coral and shells) to animals to determine the presence of acid in the stomach (4). Obviously, the degree of erosion of metal could be used as an index of gastric acidity only provided that the length of stay of the metal in the stomach remained f a i ry uniform. Observations made during an earlier study (5) suggested that variations in the length of stay of metal in the stomach might be indicated by changes in the rate of passage through the entire digestive tract. Hence, it was decided to give rats pieces of iron, steel or aluminum, note the degree of erosion or the percentage of weight lost by the metal and also note its rate of passage through the digestive tract. I t soon became evident that, in most instances, a striking increase in erosion occurred when diets low in protein were fed, but it was usually found that the passage of metal through the digestive tract was then also prolonged. Fluoroscopic observations (checked later by direct