Gh. Patterson et al., Separation of the glucose-stimulated cytoplasmic mitochondrial NAD(P)H responses in pancreatic islet beta cells, P NAS US, 97(10), 2000, pp. 5203-5207
Citations number
31
Categorie Soggetti
Multidisciplinary
Journal title
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Two-photon excitation microscopy was used to image and quantify NAD(P)H aut
ofluorescence from intact pancreatic islets under glucose stimulation. At m
aximal glucose stimulation, the rise in whole-cell NAD(P)H levels was estim
ated to be approximate to 30 mu M. However, because glucose-stimulated insu
lin secretion involves both glycolytic and Kreb's cycle metabolism islets w
ere cultured on extracellular matrix that promotes cell spreading and allow
s spatial resolution of the NAD(P)H signals from the cytoplasm and mitochon
dria. The metabolic responses in these two compartments are shown to be dif
ferentially stimulated by various nutrient applications. The glucose-stimul
ated increase of NAD(P)H fluorescence within the cytoplasmic domain is esti
mated to be approximate to 7 mu M. Likewise, the NAD(P)H increase of the mi
tochondrial domain is approximate to 60 mu M and is delayed with respect to
the change in cytoplasmic NAD(P)H by approximate to 20 sec. The large mito
chondrial change in glucose-stimulated NAD(P)H thus dominates the total sig
nal but may depend on the smaller but more rapid cytoplasmic increase.