Somatostatin activates glibenclamide-sensitive and ATP-regulated K+ channels in insulinoma cells via a G-protein |
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Authors: | M Fosset H Schmid-Antomarchi J R de Weille M Lazdunski |
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Institution: | Centre de Biochimie, Centre National de la Recherche Scientifique, Nice, France. |
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Abstract: | Somatostatin, an hyperglycemia-inducing hormone, was studied in rat insulinoma (RINm5F) cells using 86Rb+ efflux techniques. 86Rb+ efflux is stimulated by somatostatin in a dose-dependent manner. The half-maximum value of activation is 0.7 nM. Somatostatin-induced 86Rb+ efflux is abolished by the hypoglycemia-inducing sulfonylurea, glibenclamide, a known blocker of ATP-regulated K+ channels. Somatostatin activation is prevented by pretreatment of insulinoma cells with pertussis toxin. 86Rb+ efflux studies show that somatostatin activates an ATP-dependent K+ channel. |
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