Urinary excretion of uricine.

The excretion of uricine or yellowish-red pigment from uric acid stones and its binding by uric acid seems to affect the precipitation of uric acid. Uricine was determined by ion exchange chromatography followed by measurement of the alkaline fluorescence emission. The uricine urinary excretion and the uricine-uric acid potential binding were determined in 11 control subjects, 20 recurrent uric acid stone formers, seven calcium stone formers with hyperuricuria, and five gouty patients without urinary stone formation. Uricine excretion was increased in 11 uric acid stone formers, whereas it was normal in the rest of the patients. Uricine-uric acid potential binding was increased in many uric acid stone formers, despite the absence of uric acid urinary hyperexcretion, whereas it was normal in most of the calcium stone formers and was moderately increased in the gouty patients.