title: The effect of allopurinol on oxypurine excretion in xanthinuria.
abstract: In a patient with xanthine urolithiasis secondary to hereditary xanthinuria (xanthine oxidase deficiency), allopurinol administration resulted in a 20 per cent increase in oxypurine excretion and an elevation of the urinary xanthine/hypoxanthine ratio from 4.08 to 6.53. The rise in this ratio suggests that residual xanthine oxidase activity may have been present. It is possible that the excessive re-utilization of hypoxanthine and xanthine in this disease prevents the allopurinol-induced inhibition of de novo purine biosynthesis that is seen in normal subjects.
mesh_terms: D000493:Allopurinol / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008875:Middle Aged; D011687:Purines / Q000378:metabolism; D014969:Xanthine Oxidase / Q000172:deficiency*; D014970:Xanthines / Q000652:urine*
chemical_list: D011687:Purines; D014970:Xanthines; D000493:Allopurinol; D014969:Xanthine Oxidase