Contrasting effects of sulfonylurea and K+ depolarization on insulin and glucagon secretion by perifused mouse islets

Background and aims: In pancreatic beta cells KATP channels couple changes in glucose metabolism to changes in insulin secretion via depolarization of the plasma membrane. In alpha cells, in contrast, where increased glucose levels inhibit hormone secretion, their role is in dispute. Methods: Batches of 50 freshly isolated NMRI mouse islets were perifused with a HEPES-buffered Krebs-Ringer medium (2 mg/ml BSA) saturated with 95% O2 and 5% CO2, which contained the respective secretagogue. The contents of insulin and of glucagon were determined by ELISA from the same samples of the fractionated efflux. Results: In…