A comparison between intragastric titration and aspiration technique under basal conditions and after food or pentagastrin stimulation.

A total of 16 healthy subjects had gastric secretory studies where acid was either measured by the conventional aspiration technique (AT) or by intragastric titration at a pH of 5.0 (IT). In a first study food- and pentagastrin-stimulated PAO levels, both measured by IT, were within similar ranges. However, as compared to the respective AT data of the same subjects, the mean IT results were 35% higher, although both values were well correlated. In a second study a similar difference was observed between IT and AT data throughout the whole range of the pentagastrin dose-response curve. Both curves followed Michaelis-Menten kinetics and had similar Km values, while Vmax values were significantly higher at IT. This constellation excludes an increase of the gastrin sensitivity of the parietal cells as a cause for the higher IT data. It is, however, in keeping with the hypothesis that the distension stimulus present at IT potentiates the pentagastrin-stimulated acid secretion. It is likely that methodological problems such as overtitration of acid at IT and transpyloric loss of acid at AT additively contribute to the relatively large difference between AT and IT values. It is therefore not possible to fully interchange AT and IT data, despite their good correlation.