Glucose-induced increase of potassium in pancreatic beta-cells associated with reduced mobilization of the ion

The potassium contents of beta-cell-rich pancreatic islets from ob/ob-mice were measured with an integrating flame photometer. After exposure to 5 mM glucose islet potassium increased by 17 +/- 2%, no additional effect being seen with increase of the sugar to 20 mM. Glucose counteracted the loss of islet potassium obtained on removal of the ion from the incubation medium, halving the initial disappearance rate. Whereas the effect of glucose in suppressing the mobilisation of potassium was mimicked by tolbutamide and quinine, it was antagonized by diazoxide. It is concluded that the glucose interference with the outward transport of K+ is sufficient to raise the beta-cell content of the ion.