| First Author | Piston DW | Year | 1999 |
| Journal | J Biol Chem | Volume | 274 |
| Issue | 2 | Pages | 1000-4 |
| PubMed ID | 9873043 | Mgi Jnum | J:115233 |
| Mgi Id | MGI:3691164 | Doi | 10.1074/jbc.274.2.1000 |
| Citation | Piston DW, et al. (1999) Adenovirus-mediated knockout of a conditional glucokinase gene in isolated pancreatic islets reveals an essential role for proximal metabolic coupling events in glucose-stimulated insulin secretion. J Biol Chem 274(2):1000-4 |
| abstractText | The relationship between glucokinase (GK) and glucose-stimulated metabolism, and the potential for metabolic coupling between beta cells, was examined in isolated mouse islets by using a recombinant adenovirus that expresses Cre recombinase (AdenoCre) to inactivate a conditional GK gene allele (gklox). Analysis of AdenoCre-treated islets indicated that the gklox allele in approximately 30% of islet cells was converted to a nonexpressing variant (gkdel). This resulted in a heterogeneous population of beta cells where GK was absent in some cells. Quantitative two-photon excitation imaging of NAD(P)H autofluorescence was then used to measure glucose-stimulated metabolic responses of individual islet beta cells from gklox/lox mice. In AdenoCre-infected islets, approximately one-third of the beta cells showed markedly lower NAD(P)H responses. These cells also exhibited glucose dose responses consistent with the loss of GK. Glucose dose responses of the low-responding cells were not sigmoidal and reached a maximum at approximately 5 mM glucose. In contrast, the normal response cells showed a sigmoidal response with an KcatS0.5 of approximately 8 mM. These data provide direct evidence that GK is essential for glucose-stimulated metabolic responses in beta cells within intact islets and that intercellular coupling within the islet plays little or no role in glucose-stimulated metabolic responses. |
