Plasma and parathyroid tumor tissue gastrin and hyperparathyroidism.

Hyperparathyroidism has been associated with an increased incidence of duodenal ulcer, increased acid secretion, and increased plasma gastrin levels. A relationship between these changes, increased serum calcium levels, and the increased incidence of peptic ulceration has been suggested, especially since increased plasma gastrin levels, serum calcium levels, and gastric acid secretion decrease after parathyroidectomy. We have previously suggested that the decrease in plasma gastrin levels after parathyroidectomy may suggest an extragastric source of gastrin, whereas others using immunofluorescent studies have suggested that the parathyroid adenomas themselves might be the source of this gastrin. We prospectively studied in fifteen patients with primary hyperparathyroidism, plasma gastrin and serum calcium levels before and after parathyroidectomy, as well as the gastrin content of parathyroid tumor tissue. The mean basal plasma gastrin level before operation was significantly greater than that of a control group and decreased insignificantly after operation, in contrast to serum calcium levels. No positive correlation could be found between plasma gastrin and serum calcium levels before and after operation. Parathyroid tumor tissue was assayed for gastrin content by radioimmunoassay and no detectable amounts of gastrin could be recovered from any tumor. The results do not support the concept that the extragastric source of gastrin in patients with hyperparathyroidism is the parathyroid adenoma itself.