Difference in kinetics between the distal and proximal parts of the canine parietal cell mass in response to pentagastrin

Abstract

1. Dogs were provided with one denervated gastric pouch in the distal and another of equal size in the proximal part of the corpus fundus. Dose-response curves for pentagastrin were determined for acid output and mucosal blood flow, which was measured with the Neutral Red technique. 2. Maximum acid output was significantly higher for the distal (mean 165.4 mumol min-1) than for the proximal pouch (53.8 mumol). ED50 for acid output was significantly higher for the proximal (5.10 micrograms kg-1 h-1 of pentagastrin) than for the distal pouch (1.98 micrograms). 3. ED50 for blood flow did not differ significantly between the distal (0.48 microgram) and the proximal pouch (1.23 micrograms). For both pouches ED50 for blood flow was significantly lower than that for simultaneous acid output. This indicated that the rise in blood flow precedes that of acid output. 4. Regression analysis indicated similar ratios between maximum mucosal blood flow and maximum acid output for the distal (0.17 ml mumol-1) and the proximal (0.14 ml mumol-1)pouch. 5. The difference in maximum acid output between the two pouches correlates well with the known difference between distal and proximal parts in volume fraction of the parietal cells, while there is no valid explanation for the difference in ED50 for acid output. It can be excluded that these differences in acid production depend on dissimilarities in mucosal blood flow.