Gastrin cell function in familial multiple endocrine neoplasia type I

Area of Science:

• Endocrinology
• Gastroenterology
• Genetics

Background:

• Multiple endocrine neoplasia type I (MEN I) is an inherited disorder associated with tumors in endocrine glands.
• Previous research suggested potential abnormal gastrin secretion in MEN I patients without gastrin-producing tumors.
• Hyperparathyroidism is a common manifestation in MEN I patients.

Purpose of the Study:

• To investigate G-cell (gastrin-producing cell) function in patients with hyperparathyroidism within MEN I families.
• To determine if abnormal gastrin secretion occurs in MEN I gene carriers without gastrinoma.
• To identify the specific cause of abnormal gastrin secretion in the context of MEN I.

Main Methods:

• Studied 20 patients from six MEN I families with hyperparathyroidism, all obligate carriers of the MEN I gene.
• Utilized three provocation tests: secretin to detect gastrinoma, a test meal for G-cell hyperfunction, and bombesin to differentiate antral from duodenal G-cell sources.
• Measured serum gastrin responses to stimuli and assessed basal hypergastrinaemia and hyperchlorhydria.

Main Results:

• Seven patients presented with basal hypergastrinaemia and hyperchlorhydria, showing increased gastrin responses to secretin and bombesin, but normal postprandial responses.
• Thirteen patients with normal basal gastrin levels exhibited normal responses to all three stimuli.
• No evidence of G-cell hyperfunction was found in obligate MEN I gene carriers without gastrinoma.

Conclusions:

• In MEN I families, gastrinoma is the exclusive endocrine disorder responsible for abnormal gastrin secretion.
• G-cell function is confirmed to be normal in obligate carriers of the MEN I gene who do not have gastrinoma.
• These findings clarify the relationship between MEN I, hyperparathyroidism, and gastrin secretion abnormalities.