Peptic activity after the administration of Pentagastrin and in gastroduodenal disease.

The existence of more than one gastric pepsin has been reported by many authors. Herriott, Desreux, and Northrop (1940) separated two proteolytic fractions from human gastric juice by salt-fractionation methods, and similar results were described by Baker (1951) and Taylor (1959b). Using moving boundary electrophoresis, Kushner, Rapp, and Burtin (1964), Merten, Schramm, Grassmann, and Hannig (1952), and Taylor (1959a) have all identified two or more different proteolytic components in both swine and human gastric juice. Ryle and Porter (1959), Tang, Wolf, Caputto, and Trucco (1959) and Seijffers, Segal, and Miller (1963), using ion-exchange chromatography, have also isolated at least two different proteases in human gastric secretion. The two proteases most commonly isolated both digested proteins with two pH maxima, one near 2-0 the other around 3-5 (Taylor, 1959a). The third pepsin found by some authors was found by Tang and by Ryle to have a singlepH at 3.0. This, however, was only a minor component of gastric juice and was only occasionally found. There is good evidence therefore that two pepsins, and sometimes three, are present in human gastric juice. Furthermore, Taylor (1959b) has shown that these pepsins are obtainable from different parts of the stomach. Using material obtained at necropsy, he showed that one pepsin could be extracted from the fundic mucosa and the other from the pyloric mucosa. The fundic pepsin digested proteins with pH maxima at 2.2 and 3 5; the pyloric had more acidic peaks on thepH-activity curve at 1P7 and 3*1. Peptic activity/pH curves drawn in the present work have shown at some time or another five peaks of peptic activity below pH 4-5. However, three of these peaks occurred very rarely, and attention has been focused on the two peaks that were most frequently seen, namely, pH 1.8 and pH 2.2. This paper therefore first attempts to associate stimuli with the appearance of these peaks, and then to examine the occurrence of these pepsins in different conditions of the stomach in health and disease. METHOD