Tolbutamide inhibits gastrin release in man

Area of Science:

• Gastroenterology
• Endocrinology
• Pharmacology

Background:

• Gastrin plays a crucial role in regulating gastric acid secretion.
• The impact of sulfonylureas like tolbutamide on gastrin levels requires further elucidation.
• Understanding gastrin regulation is vital for managing acid-related disorders and diabetes.

Purpose of the Study:

• To investigate the effect of intravenous and oral tolbutamide on plasma gastrin levels.
• To determine if tolbutamide-induced changes in insulin and glucose influence gastrin suppression.
• To assess the relationship between gastrin suppression and gastric acid output following tolbutamide administration.

Main Methods:

• Intravenous infusion of tolbutamide in patients with atrophic gastritis, duodenal ulcer, insulin-dependent diabetes mellitus (IDDM), and healthy volunteers.
• Measurement of plasma gastrin, insulin, and blood glucose levels at baseline and post-infusion.
• Oral administration of tolbutamide in healthy volunteers.
• Assessment of basal and tetragastrin-stimulated gastric acid output.

Main Results:

• Tolbutamide significantly decreased fasting plasma gastrin in all studied groups after intravenous infusion.
• Increased plasma insulin and decreased blood glucose were observed in patients with atrophic gastritis, duodenal ulcer, and healthy volunteers, but not in IDDM patients.
• Oral tolbutamide also suppressed plasma gastrin in healthy volunteers.
• No changes in basal or stimulated gastric acid output were noted within 30 minutes post-infusion.

Conclusions:

• Tolbutamide inhibits gastrin release in humans through a mechanism independent of insulin, glucose, or acid secretion changes.
• These findings suggest a direct effect of tolbutamide on gastrin-producing cells or regulatory pathways.
• Further research is warranted to explore the clinical implications of tolbutamide's gastrin-suppressing effects.