498-501

Clinicalrheumatology, 1992, 11, N ~ 4

Renal Excretion of Urate by HyperuricaemicHyperlipidemic Patients E. C O L L A N T E S ESTEVt~Z*,**, R U I Z * , J. A I q 0 N B A R B U D O * ,

F.J. TINAHONES MADUEIqO*, A. G O N Z A L E Z M. P I N E D A PRIEGO***, P. S A N C H E Z GUIJO*

Summary

We studied the renal urate excretory function in two groups of hyperuricaemic male patients composed of individuals with associated hyperlipidemia and hyperuricaemic-normolipidemic individuals, respectively. Both the hyperlipidemia and the hyperuricaemia were primary inasmuch as none of the patients studied was obese or had an above-normal alcohol intake or blood hypertension. The results obtained show that hyperuricaemic-hyperlipidemic patients have higher serum levels of uric acid and poorer urate excretion as reflected in smaller clearance and fractioned excretion of the metabolite than hyperuricaemic-normolipidemic patients. This, in turn, suggests the occurrence of differences in the extent of the urate handling anomalies between the two groups of patients.

Key words

Hyperuricaemia, Hyperlipidemia, Renal Urate Excretion.

INTRODUCTION Co-occurrence of hyperuricaemia and renal infra-excretion of uric acid is the metabolic picture most commonly encountered in primary gout (1), most frequently as a result of impaired urate excretion. Renal excretion of uric acid, which is the main agent responsible for the concentration of urates in serum (2), takes place in four stages (3), namely: glomerular filtration, proximal tubular reabsorption, tubular secretion and post-secretory tubular reabsorption. Gouty individuals have been shown to effect inefficient active transport of uric acid and other purine metabolites (hypoxanthine and xanthine) arising from the same mechanism (4) with no associated renal pathology. It remains obscure, however, whether every form of primary hyperuricaemia conforms to the same pathogenic mechanism (5); in fact, over 70% of all cases of asymptomatic hyperuricaemia and more than 40% of those of primary gout are permanently associated with hyperlipidemia (6,7) of variable phenotypical expression (8) that can be attributed to no exogenous factor (9) and appear to share a common genetic basis (10). In previous work (11) we found significant differences in uricaemia levels between hyperuricaemic patients

*Unidad Docente de Patolog/a General, Departamento de Medicina, Universidad de Cdrdoba; **Seccidnde Reumatologia, Hospital Universitario, Cordoba; ***Departamento de Bioquimica, Biologfa Molecular y Fisiologfa, Universidad de Cdrdoba, Cdrdoba, Spain.

with and without associated hyperlipidemia which were believed to be either the expression of enhanced synthesis of uric acid by hyperuricaemic-hyperlipidemic individuals or the result of diminished excretion of urates. In the present work we investigated the renal function in hyperuricaemic-hyperlipidemic patients and compared it with that of the hyperuricaemic-normolipidemic patients in order to determine potential differences in the renal excretion of uric acid between the two groups. P A T I E N T S AND M E T H O D S Patients

We studied 25 males between 20 and 66 years of age (mean _ SD = 36_+ 10) suffering from primary hyperuricaemia (uric acid levels above 0.413 mmol/1) confirmed in two consecutive examinations carried out over an interval of 7-15 days. None of the patients was overweight (Quetelet index

Renal excretion of urate by hyperuricaemic-hyperlipidemic patients.

We studied the renal urate excretory function in two groups of hyperuricaemic male patients composed of individuals with associated hyperlipidemia and...
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