Renal urate excretion in five cases of hypouricemia with an isolated renal defect of urate transport.

Renal urate excretion was studied in two familial, one suspected familial, and two isolated cases of hypouricemia due to a renal defect. All had very low plasma urate concentrations. In four cases, the urate clearances were approximately the same as the creatinine clearances, and in one case reduced to about one-third. In all cases the urate clearances were minimally diminished by both pyrazinamide and probenecid. This renal response to the drugs is probably due to and isolated tubular defect in the reabsorptive transport mechanism of urate. Following intravenous administration of uric acid, one patient excreted uric acid in the urine more rapidly than a normal subject. In this patient, uric acid secretion from renal tubules was clearly demonstrated during infusion of uric acid. In de novo synthesis of purine, no definite abnormalities were found by incorporation of glycine-15N to uric acid.