Flow-cytometric analysis of glucose induced changes of the transmembrane potential and optical density in pancreatic islet cell suspensions.

Glucose-induced insulin release of beta cells of pancreatic islets is associated with islet cell membrane electrical activity. We measured the membrane potentials of neonatal rat islet cell suspensions by means of "optical probes" by flow cytometry. Moreover, we determined the narrow angle light scattering and light absorption in direction of the laser beam, respectively. In both these cases two or three clusters of the whole cell population showing different responses to glucose could be distinguished. Glucose-dependent depolarization as well as loss in optical density of cells of pancreatic islets should be associated with the physiological function of insulin producing beta-cells. It is concluded that changes of the membrane potential and/or optical density of islet cells produced by insulin secretagogues can be analysed by flow cytometry which might provide the basis for sorter experiments to separate specific subpopulations of cells of pancreatic islets.