Influence of Purine Content of Diet and Allopurinol on Uric Acid and Oxalate Excretion Levels
A defect of the purine salvage enzyme adenine phosphoribosyl-transferase (APRT) results in lithiasis in some but not all homozygotes for the defect. The stones are frequently mistaken for uric acid1, but are really composed of an insoluble analogue, 2,8- dihydroxyadenine (2,8-DHA), excreted in consequence of the defect (see Simmonds et al. this symposium). The present studies were an attempt to establish whether any variation in oxalate or urate excretion with diet could explain the asymptomatic status of one of two male siblings homozygous for the defect. A preliminary study of diet and allopurinol on purine excretion has been reported elsewhere2. The rationale for the investigations was based on the association frequently reported between dietary purine intake and increased uric acid levels in oxalate stone formers3, and the beneficial effect of allopurinol in reducing (a) the absorption of dietary purine in an animal model4; (b) the incidence of lithiasis in some oxalate stone formers5; (c) any further stone formation on a low purine diet in one of two siblings under investigation2.
KeywordsUric Acid Uric Acid Level Urinary Oxalate Oxalate Excretion Urinary Oxalate Excretion
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