INSULIN RELEASE BY ISOLATED PANCREATIC ISLETS OF MOUSE INCUBATED IN VITRO

The release of insulin during incubation of mouse islets of Langerhans, isolated after digestion of the pancreas with collagenase, has been studied, and the influence of various factors on the rate of release investigated. Glucose at 3.0 mg/ml (high glucose) stimulated insulin release, but had no effect at 0.6 mg/ml (low glucose). Mannoheptulose blocked the stimulation by high glucose, as did adrenaline. The adrenaline effect was abolished by phentolamine, an alpha-adrenergic blocking agent. Glucagon alone, stimulated insulin release, and also with low glucose, but not consistently with high glucose. Adrenaline abolished the stimulation by glucagon. Theophylline stimulated release with low glucose, much less so with high glucose and not at all with glucagon at either glucose concentration. Tolbutamide stimulated release with low glucose, and this effect was not inhibited by adrenaline. The suitability of this preparation for studies of islet cell metabolism and its relationship to secretion of insulin is discussed. © 1969 Springer-Verlag.