Diabetologia
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The dose as well as the time kinetics of insulin and adenosine-3',5'-monophosphate (cyclic AMP) responses to glucose were compared in pancreatic islets isolated from normal and diabetic Chinese hamsters. The insulin content in diabetic islets was about one-half that in normal islets. Insulin release in diabetic islets incubated for 10 min with glucose 60-1000 mg/100 ml was from one-third to one-half that in normal islets. ⋯ Also, in perifusion experiments with 0.1 mM IBMX, glucose 500 mg/100 ml produced threefold greater increases in insulin release and two-fold greater increases in efflux of cyclic AMP in normal than diabetic islets. By contrast with the lesser effects of glucose in diabetic islets, 1.0 mM IBMX increased islet and medium cyclic AMP, as well as insulin release, similarly in normal and diabetic islets. It is suggested that the impairment of glucose-induced insulin release in islets of the diabetic Chinese hamster may be due to a defective interaction of glucose with the adenylate cyclase-cyclic AMP system in the pancreatic B cell.