Abstract
Low doses of ouabain stimulate Na+, Cl-, water and perhaps K+ reabsorption by chicken kidney tubules. High doses have an opposite effect, that of inhibiting the reabsorption of these substances.
Low concentrations of ouabain stimulate Na+-K+ activated ATP-ase extracted from chicken kidney. High concentrations inhibit this activity.
The inhibitory effects of ouabain on Na+-K+ ATP-ase activity are antagonized by excess K+.
Because of the correlations of effects produced by ouabain on ion transport in vivo and Na+-K+ ATP-ase activity in vitro, it is proposed that the action of ouabain on electrolyte transport in the chicken kidney is mediated through Na+-K+ ATP-ase, localized in the renal tubular membrane.
A possible analogy of the effect of ouabain on renal tubular stimulation of ion transport to the inotropic action of cardiac glycosides is discussed.
Footnotes
- Accepted June 17, 1964.
- The Williams & Wilkins Comapny
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