Effect of drugs that alter uric acid excretion in man on uric acid clearance in the chicken

Abstract

In 43 chickens, the mean C_inulin was 4.7 ± 1.8 ml/min. (1.8 ± 0.8 ml/kg/min.), mean C_urate 29.0 ± 14.9 ml/min. (11.3 ± 6.0 ml/kg/min.) and mean T_urate 1.30 ± 0.69 mg/min. (0.48 ± 0.24 mg/kg/min.). Tubular secretion accounted for a mean of 81% of the total urinary urate. Probenecid, sulfinpyrazone, zoxazolamine and high dosages of phenylbutazone, all uricosuric in man, reduced urate excretion in the chicken, apparently by suppressing tubular secretion of urate; C_PAH also was reduced. Salicylate, in doses uricosuric in man, had no effect on chicken urate excretion. Pyrazinamide and sodium r-lactate, agents which decrease urate excretion in man, did not alter urate excretion in the chicken. PAH loading experiments demonstrated that as T_PAH increased, T_urate decreased. These latter findings suggest competition of urate and PAH for renal tubular transport in the chicken.