MACROMOLECULAR SECRETION BY ISOLATED GASTRIC-MUCOSA - FUNDAMENTAL DIFFERENCES IN PEPSINOGEN AND INTRINSIC-FACTOR SECRETION

  • 1 January 1978
    • journal article
    • research article
    • Vol. 74  (3) , 535-539
Abstract
The secretion of pepsinogen and intrinsic factor (IF) in response to various known stimulators and inhibitors of gastric acid secretion was examined in isolated rabbit gastric mucosa maintained in organ culture. Acetylcholine (10-8 M) stimulated both pepsinogen (P < 0.01) and IF (P < 0.01) secretion, and this stimulation was blocked by atropine. Parasympatholytic agents did not alter unstimulated (basal) secretion of pepsinogen even at high concentrations (atropine, 10-2 M or propanthelene bromide, 5 .times. 10-3 M), however, at these concentrations basal IF secretion was abolished. Histamine (10-4 and 10-2 M) had no effect on pepsinogen secretion but stimulated IF secretion (P < 0.001). Antagonism of H[Histamine]2 receptors by cimetidine reduced both basal and histamine-stimulated IF secretion, but pepsinogen secretion remained unaltered. Under the conditions of the above experiments the gastric mucosal surface was not exposed to HCl but was constantly buffered by culture medium at pH 7.4. When 50 mN HCl was applied to the mucosal surface of the biopsies, pepsinogen secretion doubled (P < 0.001) but IF secretion was abolished. Fundamental differences exist in the responses of pepsin and IF secreting cells and H+ bathing the mucosal surface of the stomach may influence the results of experiments designed to examine the mechanisms of gastric mucosal macromolecular secretion.

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