Difference in calcium dependency of insulin, glucagon and somatostatin secretion in response to glibenclamide in perfused rat pancreas
- 1 June 1982
- journal article
- research article
- Published by Springer Nature in Diabetologia
- Vol. 22 (6), 475-479
- https://doi.org/10.1007/bf00282593
Abstract
The extracellular calcium requirements for insulin, glucagon and somatostatin release induced by 1 μg/ml of glibenclamide have been compared in the perfused, isolated rat pancreas. In the absence of glucose, the drug evoked insulin release equally well at physiological (2.6 mmol/l) and low (0.25 mmol/l) levels of total calcium. In contrast, glibenclamide evoked somatostatin release at 2.6 but not at 0.25 mmol/l of calcium. At 2.6 mmol/l of calcium, glibenclamide evoked bimodal effects (stimulation followed by inhibition) on glucagon secretion. At 0.25 mmol/l of calcium, basal secretory rates of glucagon were elevated and a small stimulatory effect of glibenclamide was seen. Addition of 0.5 mmol/l of EGTA to media with low calcium concentrations uniformly abolished the A, B and D cell secretory responses to glibenclamide. The possible modulation of calcium dependency by a non-stimulatory concentration of glucose was tested by its addition at 3.3 mmol/l to the perfusion media. Glucose enhanced glibenclamide-induced insulin secretion, both at 0.25 and 2.6 mmol/l of calcium. However, at 0.25 mmol/l of calcium, the enhancing effect of glucose was more pronounced than at 2.6 mmol/l. At 2.6 mmol/l of calcium, glucose diminished the somatostatin and abolished the glucagon response to glibenclamide. At 0.25 mmol/l of calcium, glucose did not influence somatostatin release while the presence of the sugar diminished basal and glibenclamide-induced glucagon secretion. The present data confirm the requirement of extracellular calcium for A, B and D cell secretion, demonstrating different calcium dependencies for the cell types and indicate that this dependency can, in part, be modulated by glucose.This publication has 27 references indexed in Scilit:
- Intercellular Communication in Pancreatic Islet Monolayer Cultures: A Microfluorometric StudyScience, 1979
- Characterisation of somatostatin release from the pancreasDiabetologia, 1979
- REGULATION OF CALCIUM FLUXES AND THEIR REGULATORY ROLES IN PANCREATIC ISLETS*Annals of the New York Academy of Sciences, 1978
- Calcium, glucose and glucagon releaseDiabetologia, 1977
- The role of calcium in glucagon release, interactions between glucose and calciumDiabetologia, 1976
- Stimulation of insulin release after raising extracellular calciumFEBS Letters, 1976
- Stimulation of insulin release by calciumBiochemical and Biophysical Research Communications, 1975
- The stimulus-secretion coupling of glucose-induced insulin release XII. Effects of diazoxide and gliclazide upon45calcium efflux from perifused isletsDiabetologia, 1973
- The Stimulus‐Secretion Coupling of Glucose‐Induced Insulin Release VIII. Combined Effects of Glucose and Sulfonylureas*European Journal of Clinical Investigation, 1972
- Etude expérimentale d'un nouveau sulfamide hypoglycémiant particulièrement actif, le HB 419 ou glibenclamideDiabetologia, 1969