Pentagastrin dose-response in peptic ulcer disease

Area of Science:

• Gastroenterology
• Physiology

Background:

• Peptic ulcer disease diagnosis relies on assessing gastric acid and pepsin secretion.
• Pentagastrin stimulation is used to evaluate these secretory functions.

Purpose of the Study:

• To compare the diagnostic utility of pentagastrin dose-response curves versus single-dose stimulation for differentiating peptic ulcer disease (PUD) subtypes.
• To analyze acid and pepsin secretion parameters (Vmax, Km) in healthy volunteers and patients with duodenal (DU), pyloric (PU), and gastric ulcers (GU).

Main Methods:

• Administered stepwise increasing doses of pentagastrin (0.166, 1, and 6 mug/kg-hr) to 21 healthy volunteers and 81 patients with PUD.
• Measured maximal acid and pepsin secretion (Vmax) and pentagastrin sensitivity (Km).
• Compared diagnostic discrimination between groups using different stimulation levels and secretory products.

Main Results:

• Duodenal ulcer (DU) patients exhibited markedly elevated acid and pepsin secretion compared to non-ulcer groups.
• Pepsin secretion was proportionally more increased than acid secretion in DU patients.
• Pepsin secretion provided better discrimination between DU and non-ulcer groups than acid secretion, especially at higher stimulation levels.
• A submaximal pentagastrin dose (1 mug/kg-hr) showed superiority for acid secretion discrimination.
• Vmax did not offer superior diagnostic discrimination; Km values were poorly reproducible and had limited diagnostic significance.

Conclusions:

• Pentagastrin dose-response testing does not offer significant diagnostic advantages over a single, standardized dose (1 mug/kg-hr).
• This single dose is optimal for pepsin secretion assessment and submaximal for acid secretion, providing sufficient diagnostic information.
• The study highlights altered parietal and chief cell sensitivity in DU patients.