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Control of tissue progastrin concentrations in the rat
A Varro1, B Yegen, G J Dockray
1Physiological Laboratory, University of Liverpool.
Experimental Physiology
|May 1, 1993
Summary
Fasting significantly reduces plasma gastrin levels, but omeprazole reverses this effect. Stomach acid changes influence progastrin conversion to active gastrin, impacting hormone regulation.
Area of Science:
- Gastroenterology
- Endocrinology
- Physiology
Background:
- Gastrin is a key hormone regulating gastric acid secretion.
- Progastrin is the precursor to active gastrin.
- Gastrin release is influenced by physiological stimuli and feedback mechanisms.
Purpose of the Study:
- To investigate the impact of physiological stimuli (fasting, omeprazole) on plasma gastrin and tissue progastrin levels in rats.
- To understand how gastric acid inhibition affects gastrin precursor conversion and secretion.
Main Methods:
- Radioimmunoassay was used to measure plasma gastrin and tissue progastrin concentrations.
- Size exclusion chromatography was employed for progastrin measurement.
- Experiments involved conscious rats under conditions of ad libitum feeding, fasting, and omeprazole treatment.
Main Results:
- Fasting decreased plasma gastrin by 4-fold, an effect reversed by omeprazole.
- Omeprazole increased plasma gastrin 8-fold in fed rats.
- Fasting reduced tissue progastrin by 3-fold; omeprazole partially reversed this.
- Progastrin conversion to amidated gastrin increased 7-fold in fed omeprazole-treated rats.
Conclusions:
- Changes within the stomach lumen significantly influence progastrin conversion to active amidated gastrin.
- Gastrin secretion and processing are dynamically regulated by physiological states and acid levels.