Abstract
Canrenone inhibits 30-40% of ouabain-sensitive Na+ efflux in human red cells. Half-maximal inhibition was obtained with a canrenone concentration = 86 +/- 37 mumol/l (mean +/- SD of 13 experiments). The partial inhibition of the Na+,K+ pump appears to be mediated at the digitalis receptor site with an apparent dissociation constant (Kc) = 200 +/- 130 mumol/l (mean +/- SD). Further evidence suggesting that canrenone is a partial agonist at the digitalis receptor site was obtained by the observation that it decreases the apparent affinity of the Na+,K+ pump for external K+. However, in contrast to ouabain, canrenone decreases the apparent pump affinity for internal Na+. Our results show that, at physiological cell Na+ levels canrenone is able to enhance the inhibition of the Na+,K+ pump by low doses of ouabain. Conversely, in cells treated with high concentrations of cardiac glycosides (in which cell Na+ content increases), canrenone is able to restimulate the blocked pumps.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
