Abstract
Recent studies have suggested that patients with multiple endocrine neoplasia type I (MEN I) may have abnormal serum gastrin secretion in the absence of gastrin producing tumours. G-(gastrin) cell function by three provocation tests in 20 patients with hyperparathyroidism from six MEN I-families were studied: each patient was an obligate carrier of the MEN I-gene. The serum gastrin response to secretin was used to identify the presence of gastrinoma, that to a test meal of G-cell hyperfunction of the antral and/or duodenal mucosa, and that to bombesin to differentiate antral from duodenal G-cell hyperfunction. Seven patients had basal hypergastrinaemia and hyperchlorhydria. These patients had increased serum gastrin responses to secretin (p less than 0.01) and to bombesin (p less than 0.02), but normal postprandial responses. In the 13 normogastrinaemic patients the responses to the three stimuli were normal. In families with MEN-I gastrinoma is the only endocrine disorder accounting for abnormal gastrin secretion. G-cell function is normal in obligate carriers of the MEN I-gene.