| Autor: |
Elmi, A., Idahl, La, Sandström, Pe, Sehlin, J. |
| Jazyk: |
angličtina |
| Rok vydání: |
2000 |
| Zdroj: |
Karolinska Institutet |
| ISSN: |
1560-4284 |
| DOI: |
10.1155/EDR.2000.155 |
| Popis: |
To determine the effect of D-glucose on the β-cell Na+/k+ pump, R86b+ influx was studied in isolated, -cell-rich islets of Umeå-ob/ob mice in the absence or presence of lmM ouabain. D-glucose (20 mM) stimulated the ouabain-sensitive portion of R86b+ influx by 65%, whereas the ouabain-resistant portion was inhibited by 48%. The Na+/k+ ATPase activity in homogenates of islets of Umeå-ob/ob mice or normal mice was determined to search for direct effects of D-glucose. Thus, ouabain-sensitive ATP hydrolysis in islet homogenates was measured in the presence of different D-glucose concentrations. No effect of D-glucose (3–20 mM) was observed in either ob/ob or normal islets at the optimal Na+/k+ ratio for the enzyme (135 mM Na+ and 20 mM K+). Neither D-glucose (3–20 mM) nor L-glucose or 3-O-methyl-D-glucose (20 mM) affected the enzyme activity at a high Na+/k+ ratio (175 mM Na+ and 0.7mM k+). Diphenylhydantoin (150 μM) decreased the enzyme activity at optimal Na+/k+ ratio, whereas 50 μM of the drug had no effect. The results suggest that D-glucose induces a net stimulation the Na+/k+ pump of β-cells in intact islets and that D-glucose does not exert any direct effect on the Na+/k+ ATPase activity. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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