Potassium depletion increases potassium clearance capacity in skeletal muscles in vivo during acute repletion

Henning Bundgaard, Keld Kjeldsen

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    Abstrakt

    Muscular K uptake depends on skeletal muscle Na-K-ATPase concentration and activity. Reduced K uptake is observed in vitro in K-depleted rats. We evaluated skeletal muscle K clearance capacity in vivo in rats K depleted for 14 days. [3H]ouabain binding, α1, and α2 Na-K-ATPase isoform abundance, and K, Na, and Mg content were measured in skeletal muscles. Skeletal muscle K, Na, and Mg and plasma K were measured in relation to intravenous KCl infusion that continued until animals died, i.e., maximum KCl dose was administered. In soleus, extensor digitorum longus (EDL), and gastrocnemius muscles K depletion significantly reduced K content by 18%, 15%, and 19%, [3H]ouabain binding by 36%, 41%, and 68%, and α2 isoform abundance by 34%, 44%, and 70%, respectively. No significant change was observed in α1 isoform abundance. In EDL and gastrocnemius muscles K depletion significantly increased Na (48% and 59%) and Mg (10% and 17%) content, but only tendencies to increase were observed in soleus muscle. K-depleted rats tolerated up to a fourfold higher KCl dose. This was associated with a reduced rate of increase in plasma K and increases in soleus, EDL, and gastrocnemius muscle K of 56%, 42%, and 41%, respectively, but only tendencies to increase in controls. However, whereas K uptake was highest in K-depleted animals, the K uptake rate was highest in controls. In vivo K depletion is associated with markedly increased K tolerance and K clearance despite significantly reduced skeletal muscle Na-K-ATPase concentration. The concern of an increased risk for K intoxication during K repletion seems unwarranted.

    OriginalsprogEngelsk
    Sider (fra-til)C1163-C1170
    TidsskriftAmerican Journal of Physiology - Cell Physiology
    Vol/bind283
    Udgave nummer4 52-4
    StatusUdgivet - 1 okt. 2002

    Fingeraftryk Udforsk hvilke forskningsemner 'Potassium depletion increases potassium clearance capacity in skeletal muscles in vivo during acute repletion' indeholder.

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