Abstract
The inhibition of passive K+ influx into human red blood ceils (RBC) by loop diuretics was found to be dependent on the external Na+ concentration, In the absence of external Na+, there was minimal inhibition but the influx remained dependent on CI- ions. Thus, raising the external Na+ concentration increased the affinity of the putative (Na+, K+, Cl- cotransport system in human RBC for loop diuretics.