RT Journal Article
SR Electronic
T1 INTERACTION OF OUABAIN AND K<sup>+</sup> <em>IN VIVO</em> WITH RESPECT TO RENAL ADENOSINE TRIPHOSPHATASE ACTIVITY AND Na<sup>+</sup> REABSORPTION
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 558
OP 562
VO 176
IS 3
A1 NELSON, JAMES ARLY
A1 NECHAY, BOHDAN R.
YR 1971
UL http://jpet.aspetjournals.org/content/176/3/558.abstract
AB K+ antagonizes the inhibition of adenosine triphosphatase (ATPase) activity by ouabain in vitro and the natriuretic response to ouabain. To determine the effect of K4 on ATPase inhibition in vivo, ouabain (1 ıg/kg/min for 20 minutes) was infused into the left renal artery alone or with KCI (400 ıEq/min). Na+ reabsorption was determined two hours after the infusion. Kidneys were then removed and ATPase activity was determined in homogenates of the entire kidneys or in microsomal fractions of cortex and outer medulla. In the infused kidney ouabain reduced Naı reabsorption and the renal ATPase activity. K’ antagonized these effects of ouabain at calculated peritubular fluid concentrations similar to the concentrations which antagonized the inhibition of ATPase in vitro. Ouabain did not change renal blood flow, at the dose employed, as measured by an electromagnetic blood flow meter during the infusion of the drug. The ratio of p-aminohippurate excretion rate from the left over the right kidney was not changed during the infusion of Kı into the left renal artery. K’ by itself was without effect on Na4 excretion of renal ATPase activity at the time the interaction of ouabain and K+ was studied. These in vivo observations indicate that ouabain reduces Na+ reabsorption by inhibiting renal Na+ + K+ ATPase and strengthen the hypothesis that this enzyme system plays a role in renal Na+ reabsorption. © 1971 by The Williams &amp; Wilkins Co.