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Glucagon and insulin secretion during acid-base alterations
Acta Diabetologica Latina
|July 1, 1983
Summary
Alkaline extracellular pH (7.8) enhances glucagon secretion from A-cells but reduces insulin secretion from B-cells in the perfused rat pancreas. This pH shift impacts islet cell response to glucose and arginine stimuli.
Area of Science:
- Endocrinology
- Pancreatic Physiology
- Cellular Signaling
Background:
- Previous research indicated that elevated extracellular pH (7.8) impairs B-cell responsiveness to glucose, arginine, and tolbutamide.
- Understanding the precise effects of extracellular pH on pancreatic islet hormone secretion is crucial for metabolic research.
Purpose of the Study:
- To investigate the impact of extracellular pH modifications on glucose- and arginine-stimulated glucagon and insulin secretion.
- To elucidate the differential responses of A-cells and B-cells to changes in extracellular pH.
Main Methods:
- Utilized a perfused rat pancreas model to assess hormone secretion.
- Manipulated extracellular pH levels (7.4 and 7.8) during stimulation with varying glucose and arginine concentrations.
Main Results:
- Extracellular alkalosis (pH 7.8) significantly increased arginine-induced glucagon secretion compared to pH 7.4.
- A rapid, transient glucagon release was observed upon switching from pH 7.4 to 7.8 during stimulation.
- Elevated pH (7.8) enhanced glucagon output while markedly reducing insulin secretion in response to glucose and arginine.
Conclusions:
- Extracellular pH plays a significant regulatory role in both glucagon and insulin release from pancreatic islets.
- Extracellular alkalosis potentiates A-cell secretion in response to glucose and arginine, concurrently inhibiting B-cell function.