Acid Secretory Responses to Histamine and the Parietal Cell Mass in the Dog

Abstract

Gastric secretion in response to graded doses of histamine, given subcutaneously at 10-minute intervals, was obtained from whole stomachs in acute experiments on six anesthetized dogs. Extragastric contamination was excluded. Each dose was maintained until a steady rate of secretion was reached, after which the dose was increased. The experiment was continued until a maximal secretory response was attained. The log dose/response curves for rates of secretion attained with different doses, corresponding acid outputs and, in some experiments, acid concentration, were normal-sigmoid in character. The maximal secretory responses were greater than those previously observed in the intact and the vagally denervated total pouch dog, although the histamine dosages found necessary to effect these responses were within the previously reported range. The total number of parietal cells in the stomach, estimated by a technique previously employed in guinea pigs and man, ranged from 1.2 to 1.6 billion. The magnitudes of both the maximal secretory response and the parietal cell mass in the dog were similar to the respective values reported in human beings free of gastroduodenal ulceration.