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Ca++ and pancreatic amylase release.
The American Journal of Physiology
|June 1, 1975
Summary
Calcium ions (Ca++) are crucial for pancreatic amylase release. Studies show extracellular calcium is not essential for triggering enzyme release but may regulate the process.
Area of Science:
- Physiology
- Cell Biology
- Biochemistry
Background:
- Pancreatic enzyme secretion is a complex process involving calcium ions.
- The precise role of extracellular calcium in regulating amylase release remains under investigation.
Purpose of the Study:
- To investigate the role of extracellular calcium (Ca++) in regulating amylase release from mouse pancreatic tissue.
- To determine if calcium influx is essential for triggering bethanechol-stimulated amylase secretion.
Main Methods:
- Superfusion of mouse pancreatic fragments with calcium-depleted media.
- Measurement of amylase release in response to the cholinergic agonist bethanechol.
- Utilizing radioactive calcium-45 (45Ca++) to study calcium uptake and efflux dynamics.
Main Results:
- Bethanechol-stimulated amylase release was significantly reduced in zero calcium (0 Ca++) medium.
- Normal amylase release was observed even after substantial calcium washout, suggesting extracellular calcium is not critical for triggering.
- Calcium-45 uptake was multiphasic and unaffected by bethanechol; however, bethanechol enhanced 45Ca++ efflux.
Conclusions:
- Extracellular calcium and/or calcium influx are not the primary triggers for pancreatic enzyme release.
- Extracellular calcium likely plays a regulatory role in both basal and stimulated amylase secretion from pancreatic tissue.