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Oscillatory insulin secretion in perifused isolated rat islets
R W Bergstrom1, W Y Fujimoto, D C Teller
1Department of Medicine, University of Washington, Seattle 98195.
The American Journal of Physiology
|October 1, 1989
Summary
Isolated rat islets exhibit synchronized, oscillatory insulin secretion in response to glucose. This intrinsic islet pacemaker activity, independent of neural input, is metabolically regulated, suggesting a unified mechanism across organisms.
Area of Science:
- Endocrinology
- Cellular Physiology
- Metabolic Regulation
Background:
- Insulin secretion is crucial for glucose homeostasis.
- Previous studies identified first- and second-phase insulin release.
- The existence and regulation of oscillatory insulin secretion were not fully understood.
Purpose of the Study:
- To investigate the oscillatory nature of insulin secretion from isolated rat islets.
- To determine if glucose stimulation can synchronize islet activity.
- To explore the metabolic regulation of these oscillations.
Main Methods:
- Perifusion of isolated rat islets of Langerhans.
- Step-function increase in glucose concentration.
- Monitoring of insulin secretion over time.
Main Results:
- Sustained, synchronized oscillations in insulin secretion were observed.
- A consistent periodicity of approximately 16 minutes was established.
- Theophylline prolonged the oscillatory period, indicating metabolic regulation.
Conclusions:
- Isolated islets possess an intrinsic oscillatory pacemaker for insulin secretion.
- Glucose stimulation synchronizes islet activity without neural inter-islet communication.
- Metabolic factors, like theophylline, can modulate the periodicity of insulin secretion.