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 NaCI-restricted diet in two groups of untreated subjects with low (117-207 nmol per litre of cells perh) and high (373-598 nmol per litre of cells perh) 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 < 0.05); this group also had a significantly reduced fractional excretion of uric acid with the NaCI-restricted diet even after adjustment for the difference in blood pressure (P < 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 counter-transport.