Altered renal tubular function in men with high erythrocyte sodium-lithium countertransport

The renal fractional excretion of uric acid was determined for both a habitual diet and an NaCl-restricted diet in two groups of untreated subjects with low (117-207 mumol per litre of cells per h) and high (373-598 mumol per litre of cells per h) erythrocyte Na-Li countertransport identified in a population-based survey of middle-aged male workers. The group with high Na-Li countertransport had a higher mean blood pressure (P less than 0.05); this group also had a significantly reduced fractional excretion of uric acid with the NaCl-restricted diet even after adjustment for the difference in blood pressure (P less than 0.03). These findings are compatible with an abnormality in kidney tubular function and possibly in the renal handling of sodium in subjects with elevated erythrocyte Na-Li countertransport.