The renal handling of sodium and potassium in environmental cadmium-exposed subjects with renal dysfunction

Abstract

To clarify using clearance methods the renal handling of sodium and potassium in a population with environmental cadmium (Cd)-induced renal dysfunction, 76 Cd-exposed subjects (32 men and 44 women) and 36 non-exposed subjects (18 men and 18 women) were selected. Fractional excretions of potassium and β 2-microglobulin were higher in the Cd-exposed subjects than in the non-exposed subjects, while the fractional excretion of sodium in the Cd-exposed subjects was equal to that of the non-exposed subjects. The urinary excretion rate of sodium was significantly lower in the Cd-exposed subjects than in the nonexposed subjects, while no significant difference was found in the urinary potassium excretion rate. Fractional excretion of sodium showed a significant correlation with age in all the subjects, while that of potassium significantly correlated with serum β 2-microglobulin. These results indicate that increases in the fractional excretion of sodium or potassium do not directly signify increased urinary excretion of sodium or potassium in Cd-induced renal tubular dysfunction. The fractional excretion of potassium may be more affected by Cd-induced renal dysfunction, while that of sodium appears to be more related to age.