A modified and sensitive method for acid secretion studies in human gastric glands isolated from gastroscopic biopsy specimens

In vitro studies of physiologic, pathologic and pharmacologic conditions of human parietal cell functioning strongly need a simple and sensitive test, which can be performed on few, single patient gastroscopic biopsy specimens. A micro-method to determine acid secretion in isolated human gastric glands by the [14C]-aminopyrine (AP) accumulation technique has been developed, however its use has been restricted by low sensitivity and cumbersome technique. The introduction of several modifications led to a much faster, less elaborate and more sensitive technique, which is hereby presented. Gastric glands were isolated from standard forceps corpus biopsy specimens by incubation with collagenase and pronase. The accumulation of [14C]-aminopyrine was used as a marker of acid production in parietal cells. NaSCN samples were used to determine non-specific binding of aminopyrine to the glands. Maximal stimulated versus basal acid secretion was obtained by incubation of 10(-3)M solutions of resp. carbachol (3.3 ± 0.3, mean ± S.E.M. of four experiments), db-CAMP (18.4 ± 1.9) and histamine (35.4 ± 4.4). Digestion of biopsy specimens by combined activity of pronase and collagenase with high specific activity allowed a 90 min. gain in separation of gastric glands. By determining both the radioactivity of the gland pellet and the supernatant and using the measurements obtained with the NaSCN tubes, it is not necessary to determine the dry weight of the glands after 10 hours drying. In conclusion, we report a simple, low radioactive, sensitive and fast (3 hour-) test for studies of human parietal cell functioning using few single patient biopsy specimens.