EFFECTS OF CERTAIN STEROIDS AND OTHER COMPOUNDS ON SODIUM EFFLUX FROM ERYTHROCYTES

Abstract

SUMMARY The effect of hormones and drugs on net sodium (Na+) efflux from human erythrocytes was studied. On cooling, the red cells gain Na+ from the extra-cellular fluid, the excess Na+ being driven out again on incubation at 37° C. This net loss of Na+ from red cells was inhibited by digoxin and much larger concentrations of SC 5233, an aldosterone antagonist. The latter drug's effect was markedly enhanced by deoxycorticosterone (DOC), the combination being able to reverse the direction of Na+ flux. However, DOC alone or combined with digoxin had no influence on net Na+ efflux. Other hormones and drugs tested by the same method had no significant action on net Na+ efflux from erythrocytes. Implications of these findings are discussed.