Patterns of gastrin components in serum during feeding in normal subjects and duodenal ulcer patients

The contribution of the different gastrin components to the gastrin response to a protein-rich meal was studied. Pooled or individual samples of venous blood drawn at intervals in 12 normal subjects and 16 patients with duodenal ulcers were fractionated on Sephadex G 50 superfine columns of various lengths. Total gastrin immunoreactivity and concentrations of various components were measured radioimmunochemically. The changes in total serum concentration of immunoreactive gastrin were principally due to changes in component II ('big gastrin') and III ('little gastrin'). The predominant pattern in both groups was an early increase in component III and a later and smaller increase in component II. Total gastrin response was largest in the patients with duodenal ulcer, and this was due mainly to component III. Furthermore, fasting samples also showed a relatively higher concentration of component III in the ulcer patients. This study shows that 'little gastrin' is the more important component in the gastrin response to stimulation by food. Serum concentrations of total gastrin immunoreactivity are alike in normal subject and duodenal ulcer patients, but the findings indicate that increased levels of 'little' gastrin may be characteristic of duodenal ulcer disease. Since 'little gastrin' is more potent than 'big gastrin', this would agree with the hypersecretion of acid in duodenal ulcer.