Potassium and chloride fluxes are involved in volume regulation in mouse pancreatic islet cells

• Published in: Acta physiologica Scandinavica Vol. 128; no. 4; p. 541
• Main Authors: Lindström, P, Norlund, L, Sehlin, J
• Format: Journal Article
• Language: English
• Published: England 01.12.1986
• Subjects: Animals; Biological Transport - drug effects; Chlorides - metabolism; Glyburide - pharmacology; Islets of Langerhans - physiology; Mice; Mice, Obese; Osmolar Concentration; Ouabain - pharmacology; Potassium - metabolism; Tetracaine - pharmacology
• DOI: 10.1111/j.1748-1716.1986.tb08010.x
• ISSN: 0001-6772

Potassium and chloride transport were measured in beta-cell-rich islets from ob/ob-mice using 36Cl- and 86Rb+ (K+-analogue). Reduction of the osmolarity from the normal 317 mosm l-1 to 180 mosm l-1 reduced the apparent content of K+ and Cl-. Hypo-osmolarity had no effect on the ouabain-sensitive portion of the Rb+ influx (Na+/K+ pump), but reduced the ouabain-resistant portion of the influx. Hypo-osmolarity also strongly increased the Rb+ efflux rate. Both tetracaine (0.5 mM) and glibenclamide (20 microM), which increase the osmotic resistance of pancreatic beta cells, significantly potentiated the reduction in apparent K+ content induced by hypo-osmolarity. This study suggests that the volume regulation in pancreatic beta cells is partly due to K+ and Cl- flux and that glibenclamide and tetracaine increase the osmotic resistance of the beta cells by affecting such ion transport.