SGK1 dependence of insulin induced hypokalemia.
Pflugers Arch
; 457(4): 955-61, 2009 Feb.
Article
em En
| MEDLINE
| ID: mdl-18665390
ABSTRACT
Insulin stimulates cellular K+ uptake leading to hypokalemia. Cellular K+ uptake is accomplished by parallel stimulation of Na+/H+ exchange, Na+,K+,2Cl- co-transport, and Na+/K+ ATPase and leads to cell swelling, a prerequisite for several metabolic effects of the hormone. Little is known about underlying signaling. Insulin is known to activate the serum and glucocorticoid-inducible kinase SGK1, which in turn enhances the activity of all three transport proteins. The present study thus explored the contribution of SGK1 to insulin-induced hypokalemia. To this end, gene-targeted mice lacking SGK1 (sgk1-/-) and their wild-type littermates (sgk1+/+) have been infused with insulin (2 mU kg(-1) min(-1)) and glucose at rates leaving the plasma glucose concentration constant. Moreover, isolated liver perfusion experiments have been performed to determine stimulation of cellular K+ uptake by insulin (100 nM). As a result, combined glucose and insulin infusion significantly decreased plasma K+ concentration despite a significant decrease of urinary K+ excretion in sgk1+/+ but not in sgk1-/- mice. Accordingly, the plasma K+ concentration was within 60 min significantly lower in sgk1+/+ than in sgk1-/- mice. In isolated liver perfusion experiments, cellular K+ uptake was stimulated by insulin (100 nM), an effect blunted by 72% in sgk1-/- mice as compared to sgk1+/+ mice. Accordingly, insulin-induced cell hydration was 63% lower in sgk1-/- mice than in sgk1+/+ mice. Moreover, volume regulatory K+ release was 31% smaller in sgk1-/- mice than in sgk1+/+ mice. In conclusion, the serum and glucocorticoid-inducible kinase SGK1 participates in the signaling mediating the hypokalemic effect of insulin.
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Base de dados:
MEDLINE
Assunto principal:
Proteínas Serina-Treonina Quinases
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Proteínas Imediatamente Precoces
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Hipopotassemia
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Insulina
Limite:
Animals
Idioma:
En
Ano de publicação:
2009
Tipo de documento:
Article