ISSN:
1437-7799
Keywords:
Key words Urate excretion
;
Urate transport in nephrons
;
Hyperuricemia
;
Pyrazinamide test
;
Benzbromarone test
;
Four-component theory
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Background. Urate underexcretion has been reported as the major cause of hyperuricemia in gouty patients. The four-component theory of urate transport in nephrons has been a valuable hypothesis for studying the mechanism of the urate underexcretion, but accurate quantitative analysis of urate transport in nephrons at different sites has not yet been carried out. To determine the amount of urate transport in nephrons more accurately, we applied mathematical calculations to urate transport in nephrons based on the four-component theory. Methods. In 20 gouty patients and 14 normal controls, 60-min urine fractions and blood samples taken at the midpoint of the urine collection period were collected before and after pyradinamide or benzbromarone administration, and urate clearance (Cua) was determined. Urate excretion (Uua) was defined as {Ccr(1-R1) + Cs} Sua(1-R2), where Ccr is creatinine clearance, R1 is the presecretory reabsorption rate, Cs (ml/min) is the secretion rate, Sua is serum urate level, and R2 is the postsecretory reabsorption rate. Results. In the gouty patients, urate glomerular filtration was significantly higher than in the normal controls, but approximately 96% of the filtered urate was reabsorbed. The urate secretion rate of gouty patients was markedly lower than that of the controls, but the amount of urate secretion was slightly and not significantly lower than that of the controls. Postsecretory reabsorption was proportional to intratubular urate concentration. Subsequent urinary excretion in gouty patients was significantly lower than that in the normal controls. Presecretory reabsorption, secretion, postsecretory reabsorption, and urinary excretion comprised 95.9%, 38.9% 38.6%, and 4.4% of urate glomerular filtration in gouty patients, and 96.2%, 52.2%, 49.6%, and 6.5% in normal controls, respectively. Conclusions. Urate secretion in the nephrons of gouty patients was significantly decreased compared with that in normal controls in terms of its rate and its proportion to urate glomerular filtration, which resulted in significant reduction of urinary urate excretion.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s101570050030
