119 IMPAIRED RENAL EXCRETION OF HYPOXANTHINE (Hx) AND XANTHINE (X) IN PRIMARY GOUT

Abstract

Most patients with primary gout show normal uric acid (UA) production rates and a relative underexcretion of UA. To examine if the renal dysfunction for UA excretion in primary gout also affects the excretion of UA precursors, we compared the plasma concentrations and 24 hour urinary excretion of Hx and X in 10 normal suojects, 15 patients with primary gout and UA underexcretion and 10 patients with diverse enzyme deficiencies known to overproduce UA. All subjects showed a creatinine clearance above 80 ml/min/1.73 m2. Results (mean±SEM) were as follows Urinary UA excretion was correlated with Hx and X excretion (r=0.857; P<0.01 and r=0.927; P<0.01, respectively). A significant direct relationship was found between the renal clearances of UA, Hx and X. These results indicate that patients with gout who underexcrete UA are also underexcretors for Hx and X. The renal impairment for UA excretion in primary gout appears to be more extensive than previously recognized.