Effect of carbohydrates upon fluorescence of reduced pyridine nucleotides from perifused isolated pancreatic islets

Abstract

In perifused pancreatic islets, the fluorescence of reduced pyridine nucleotides (NAD(P)H) was measured continuously. Elevation of glucose concentration in the medium from 0 - 5 mM to 20 mM led to an increase in NAD(P)H-fluorescence beginning 10-20 sec after change of medium. Perifusion with calcium-free media had no influence on this effect. It was, however, partially or completely blocked by 2-deoxy D-glucose, D-glucosamine, or D-mannoheptulose. D-mannose, but not D-fructose and L-lactate, enhanced NAD(P)H-fluorescence from pancreatic islets. Pyruvate caused but a small fluorescence increase. From these observations it is concluded that D-glucose leads to the increase of NAD(P)H-fluorescence by mediation of the phosphoglyceraldehyde dehydrogenase reaction. © 1973 Springer-Verlag.