ISSN:
1573-904X
Keywords:
cardiac glycosides
;
ouabain
;
Na,K-ATPase
;
guinea pig
;
tissue distribution
;
tissue-to-plasma concentration ratio
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Ouabain binds specifically to Na,K-ATPase on the plasma membrane and therefore serves to measure the tissue concentration of Na,K-ATPase. We examined the role of ouabain binding to Na,K-ATPase in its overall tissue distribution. The tissue-to-plasma concentration ratio (K p,vivo) was defined in each tissue after intravenous administration of 3H-ouabain in guinea pigs, and specific binding of ouabain to Na,K-ATPase was measured in tissue homogenate to obtain the dissociation constant and binding capacity in each tissue. A predicted tissue-to-plasma concentration ratio (K p,vitro) was calculated using the obtained binding parameters and the volume of extracellular space in each tissue. The absolute values of K p,vitro were comparable to those of K p vivo, except in brain. Regression analysis showed that the specific binding capacity of Na,K-ATPase in each tissue is the main factor in the tissue variation of K p,vivo. Therefore, the binding of ouabain to Na,K-ATPase plays a significant role in the tissue distribution of ouabain.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1015832127969
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