Pepsin secretion in man after Histalog stimulation

Abstract

SUMMARY Human gastric juice shows three separable pepsin fractions on chromatography on DEAE-cellulose. The response of these fractions to stimulation with f-aminoethylpyrazole hydrochloride (Histalog) was studied. After a single intramuscular injection of Histalog (1-7 mg/kg body weight) there was an increase in the output of all three chromatographically distinguishable pepsin fractions. Little change was observed in the relative proportions of these three fractions and there was no evidence of selective stimulation of any individual fraction.Many previous studies of the secretion of pepsin in man have appeared. These, for the most part, have regarded pepsin as a single substance and have taken no account of the fact that human 'pepsin' is composed of a number of different proteinases. It now appears that human gastric mucosa contains at least seven distinguishable proteinase proenzymes (Turner, Mangla, Samloff, Miller, and Segal, 1970) which are the precursors of a number of pepsins which are found in the gastric juice. Although, as yet, it is not clear how many individual enzymes result from the activation of these zymogens, and no method has yet been developed for the quantitative measurement of each individually, Seijffers, Segal, and Miller (1964) were able to separate human pepsin into three distinct fractions which could be measured quantitatively by chromatography on DEAE-cellulose. These fractions were termed 'pepsin I', 'pepsin II', and 'pepsin III'. It is the purpose of this communication to report the results of the application of this chromatographic technique to the study of gastric juice specimens obtained from three normal subjects after stimulation with Histalog (,B-aminoethylpyrazole hydrochloride).