Dynamics of O2 consumption in rat pancreatic islets
- 1 May 1980
- journal article
- research article
- Published by Springer Nature in Diabetologia
- Vol. 18 (5), 395-405
- https://doi.org/10.1007/bf00276821
Abstract
Summary The O2 consumption of rat pancreatic islets was determined by monitoring pO2 in the perifusate from groups of 200–300 islets. Basal respiration was maintained for up to 2 h. The insulin secretagogues, glucose and 4-methyl-2-oxopentanoate, provoked an immediate (2 consumption and the ability of glucose and 4-methyl-2-oxopentanoate to increase islet respiration. 2,4-Dinitrophenol increased islet O2 consumption. The omission of Ca2+ and Mg2+ from the perifusing media, or the addition of the ionophore A23187, had little effect on respiration. The omission of K+ inhibited glucose-induced changes but had a lesser effect in the absence of substrate or in the presence of 4-methyl-2-oxopentanoate. The omission of HCO3 - reduced both basal and secretagogue-induced changes in islet respiration. It is concluded that mitochondrial O2 consumption linked to oxidative phosphorylation is a major component in the respiratory response, and that some energy consuming process in the islets depends on the availability of HCO3 -. Mitochondrial reactions may generate a signal initiating the secretory process.Keywords
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