EFFECTS OF CALCIUM ON RENAL EXCRETION OF POTASSIUM AND WATER AND ON TISSUE SOLUTE CONCENTRATIONS OF RENAL CORTEX MEDULLA AND PAPILLA

1. Infusions or injections of CaCl2 into dogs enhance the excretion of both, sodium and potassium. However, the relation of Na to K excretion is not altered. Acetazolamide or mercurial diuretics change this relation in a characteristic manner. Additional administration of CaCl2 has no further effect on the newly established relationship. It is assumed that Ca-ions have no specific influence on potassium excretion. 2. Ca-ions decrease both, {Mathematical expression} in water diuresis and {Mathematical expression} in in antidiuresis. 3. The osmolality and the concentration of sodium in the tissue of the medulla and papilla was decreased when acute hypercalcaemia was induced by the infusion of a CaCl2 solution into one renal artery for 20 min and also when the plasma calcium concentration had been increased for at least one week. Water content and potassium concentration were unchanged. 4. These results are compatible with the hypothesis that the diuresis observed in clearance experiments following infusions of calcium salts is provoked at least to some extent in the ascending limb of the loop of Henle. © 1968 Springer-Verlag.