RENAL-FUNCTION IN CYSTIC-FIBROSIS WITH SPECIAL REFERENCE TO THE RENAL SODIUM HANDLING

Renal function was studied in 16 patients with cystic fibrosis, aged 5-19 yr. The mean glomerular filtration rate and filtration fraction were increased compared to those in controls. Basal urinary Na excretion as well as renal responses to oral and i.v. sodium loads were low, indicating an increased renal Na reabsorption. Diluting capacity, measured as free water clearance, was decreased because of a low distal Na delivery which might indicate an increased proximal Na reabsorption.