Abstract
Dose-response curves were obtained from forty adult male control subjects and forty patients with duodenal ulcer by administering 1·6, 2·0, 2·4, 2·8, 3·2-mg doses of histamine acid phosphate (HAP) subcutaneously. The results showed that the minimal dose of HAP for MAO for patients with duodenal ulcer was significantly greater than that required for control subjects. A significant positive correlation between the minimal dose of HAP, independent of body weight, for MAO and the maximal acid secretory capacity of an individual was observed both in control subjects and patients with duodenal ulcer.