Separation of the glucose-stimulated cytoplasmic and mitochondrial NAD(P)H responses in pancreatic islet β cells

George H. Patterson, Susan M. Knobel, Per Arkhammar, Ole Thastrup, David W. Piston

Research output: Contribution to journalArticlepeer-review

218 Scopus citations

Abstract

Two-photon excitation microscopy was used to image and quantify NAD(P)H autofluorescence from intact pancreatic islets under glucose stimulation. At maximal glucose stimulation, the rise in whole-cell NAD(P)H levels was estimated to be ≃30 μM. However, because glucose-stimulated insulin secretion involves both glycolytic and Kreb's cycle metabolism, islets were cultured on extracellular matrix that promotes cell spreading and allows spatial resolution of the NAD(P)H signals from the cytoplasm and mitochondria. The metabolic responses in these two compartments are shown to be differentially stimulated by various nutrient applications. The glucose- stimulated increase of NAD(P)H fluorescence within the cytoplasmic domain is estimated to be ≃7 μM. Likewise, the NAD(P)H increase of the mitochondrial domain is ≃60 μM and is delayed with respect to the change in cytoplasmic NAD(P)H by ≃20 sec. The large mitochondrial change in glucose-stimulated NAD(P)H thus dominates the total signal but may depend on the smaller but more rapid cytoplasmic increase.

Original languageEnglish
Pages (from-to)5203-5207
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume97
Issue number10
DOIs
StatePublished - May 9 2000

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