Gastrin and gastric surgery.

The development of the radioimmunoassay for gastrin has resulted in significant increases in our knowledge of the physiology of the stomach and antrum, and in an objective recognition of the interaction of the gastrin and vagus mechanisms. Recent identification of multiple species of gastrin in the circulation, however, raises questions as to the significance of early experimental results. Until the various aspects of gastrin and their relative contributions in the normal state and in pathologic processes are identified, the significance of gastrin levels in the evaluation of patients with uncomplicated ulcer disease is unclear. Although many investigators have attempted to correlate changes in serum gastrin levels in response to various stimuli with the completeness of vagotomy or the likelihood of recurrence, it is too early to give any clinical significance to these reports. Several points in particular seem worthy of emphasis: 1. Preoperative serum gastrin levels are currently of no value in selecting an operation for the treatment of duodenal ulcer disease. 2. The difference in serum gastrin levels in response to feeding that may be shown to exist between groups of normal subjects and duodenal ulcer patients is not a value in diagnosing ulcer disease in a specific patient, nor in differentiating duodenal ulcer from other conditions. 3. The measurement of serum gastrin levels in association with Hollander tests, while perhaps of potential future benefit, does not improve the accuracy of the Hollander test nor do results necessarily relate to vagal innervation. 4. Postoperative serum gastrin levels are increased after vagotomy. The degree of hypergastrinemia after vagotomy does not correlate with risk of ulcer recurrence. 5. Hypergastrinemia (greater than 1000 pg. per ml.) in the presence of hyperacidity is essentially pathognomonic of the Zollinger-Ellison syndrome. Calcium and secretin infusions do not add to the diagnosis if clear-cut clinical and laboratory data are present. These differential tests are of value in identifying the Zollinger-Ellison patient who has borderline serum gastrin levels and in differentiation from the syndrome of the retained antrum. 6. In a patient with a recurrent ulcer following surgery in whom a drug-induced ulcer can be excluded and gastric outlet obstruction cannot be demonstrated, a serum gastrin level may be indicated. A serum gastrin value greater than 300 pg. per ml. (normal less than 200 pg. per ml.) in a fasting morning serum sample is significantly elevated, even after vagotomy, and warrants further investigation. Provocative testing of the gastrin response to calcium and secretin should elucidate the etiology of the recurrent ulceration in this type of patient.