The role of potassium-canrenoate in the 3H-noradrenaline uptake and metabolism of the rat heart.

The influence of potassium-canrenoate (Aldactone) on the noradrenaline (NA) uptake and metabolism of the heart was studied in normal and hypopotassemic rats. The administration to normal rats resulted in a marked increase of 3H-NA uptake both in the atrial and ventricular tissues, but the NA content was unchanged. An increased NA uptake of myocardium in the presence of an unchanged content suggested an increased rate of NA turnover under the influence of the drug. In saluretic pretreated animals the substance normalized both the previously decreased NA uptake and the low intracellular potassium level of the heart tissue. The augmentation of catecholamine metabolism due to the drug may be involved in an enhanced activity of adenyl cyclase and form the basis of the positive inotropic effect of the compound.