Abstract: | Ultrastructural changes taking place in various phases of secretion in the gastric fundus parietal cells after histamine adminstration were studied in patients suffering from gastric and duodenal ulcers, having different gastric acidity. Parietal cells of patients with normal and hyperacidity of the gastric juice after histamine administration were found to have such ultrastructural alterations in which were characteristic of the intensively functioning cells, with the retention of phasic character of the process; as to patients with hypoacidity, the secretory phases of the parietal cells were not marked, and no alterations indicating intensification of the cellular functional activity were noted. |