Endogenous Ouabain and Its Binding Globulin: Effects of Physical Exercise and Study on the Globulin's Tissue Distribution

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Author(s)

    • BAUER Natali
    • Clinic of Internal Medicine of Small Animals, Faculty of Veterinary Medicine, Justus-Liebig-University Giessen, Giessen, Germany
    • NEU Horst
    • Clinic of Internal Medicine of Small Animals, Faculty of Veterinary Medicine, Justus-Liebig-University Giessen, Giessen, Germany
    • GRUNBAUM Ernst-Gunther
    • Clinic of Internal Medicine of Small Animals, Faculty of Veterinary Medicine, Justus-Liebig-University Giessen, Giessen, Germany

Abstract

Ouabain, that has been isolated from bovine adrenals and hypothalamus, is a new cardiotonic steroid hormone, which is either synthesized in the adrenals or stored there after it has absorbed from the diet. Little is known <i>in vivo</i> which events may lead to the release of ouabain into blood. Moreover, a binding protein for cardiotonic steroids exists in blood, which binds cardiac glycosides with high affinity. It may affect the action of endogenous ouabain on heart and circulation, but the physiological function of this protein is unclear. To realize, which physiological stimuli <i>in vivo</i> may affect blood concentrations of endogenous ouabain and which function the cardiotonic binding protein may have in modulating ouabain effects, the effect of physical exercise on endogenous ouabain was studied and the tissue distribution of its binding protein was investigated. We found that endogenous ouabain changes rapidly in blood upon physical exercise and behaves like expected for a hormone of circulation. The cardiotonic steroid binding globulin shows the highest concentration in the kidney, which suggests that sodium pumps of the kidney are protected against its inhibition by ouabain which would lead not only to natriuresis but also to a deleterious loss of glucose, amino acids and phosphate. (<i>Hypertens Res</i> 2000; 23 Suppl: S93-S98)

Journal

  • Hypertension Research

    Hypertension Research 23, S93-S98, 2000-09-01

    The Japanese Society of Hypertension

References:  33

Cited by:  1

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