Relationship between insulin- and histamine-stimulated gastric secretion before and after vagotomy

The relationship of gastric secretion in response to a single injection of insulin and in response to a histamine infusion, in unoperated patients with duodenal ulcer was studied before and after vagotomy. The secretion in response to insulin was significantly less than that in response to histamine. The ratio was about 0.7 before vagotomy, and about 0.4 after vagotomy irrespective of the adequacy of vagotomy. Highly significant correlations were obtained between the responses to the two stimuli, both in the unoperated group and in the whole postoperative group as well as in the inadequate vagotomy group, but not in patients after adequate vagotomy. Thus, the proportional differences between individuals in response to insulin were substantially the same as the proportional differences in response to histamine. The algebraic excess of histamine- over insulin-stimulated secretion before vagotomy did not differ from the value after vagotomy. Histamine-stimulated secretion after adequate vagotomy approximated to, but after inadequate vagotomy was greater than the preoperative algebraic excess of histamine- over insulin-stimulated secretion. These results are consistent with a new model of acetylcholine/histamine-receptor relationships. A certain proportion of the parietal cells are insensitive to the vagus but sensitive to histamine; and those sensitive to the vagus are also sensitive to histamine, but only when their vagal innervation is intact.