Characteristics of Active Sodium and Potassium Transport in Erythrocytes in Children With Differentstages of Symptomatic Uremia

Sigström, L. (Department of Paediatrics I, University of Göteborg, East Hospital, Göteborg, Sweden). Characteristics of active sodium and potassium transport in erythrocytes in children with different stages of symptomatic uremia. Acta Paediatr Scand, 70: 361, 1981.–Erythrocytes from 15 uremic children aged from 7 months to 16 years were analyzed for adenosine triphosphatase (total ATPase and ouabain sensitive ATPase i.e. Na + , K + ‐ATPase), sodium and potassium ions and ATP concentration, in some cases before and after therapeutic measures had been undertaken. No correlation was found between the levels of Na + , K + ‐ATPase and serum creatinine and all uremic children had Na + , K + ‐ATPase levels within the range for normal children. The children with rapidly progressive uremia had higher activities of Na + , K + ‐ATPase at the corresponding serum creatinine concentration than those with slowly progressive uremia. Longitudinally the Na + , K + ‐ATPase activities fell and the erythrocyte Na + ‐K + ratio increased in slowly progressive uremia. Introduction of a low‐protein, high‐energy diet giving accelerated growth did not change the Na + , K + ‐ATPase activities, the concentrations of erythrocyte sodium and potassium ions or ATP. Hemodialysis gave a slight increase of Na + , K + ‐ATPase and of the erythrocyte Na + ‐K + ratio, whereas renal transplantation resulted in a remarkable increase of Na + , K + ‐ATPase activity and decrease of Na + ‐K + ratio. A distinct feature of uremic children with hypertension was a low erythrocyte Na + ‐K + ratio and a high Na + , K + ‐ATPase level.