Abstract
A notable increase in uric acid and glucose excretion was observed in a patient with juvenile rheumatoid arthritis (Still's disease) while receiving cortisone and also when given ACTH. The parallelism between observed values of uric acid and glucose was impressive and suggested the need to check the effect of glucose on the values obtained for uric acid by the method used. The method for the determination of uric acid was that of Buchanan, Block and Christman(l) in which uric acid is determined as the difference in values obtained before and after digestion with the enzyme uricase. Application of this method to solutions of uric acid, of glucose, and of mixtures of uric acid and glucose gave the following results:
a. Color formation from given amounts of glucose and of uric acid in mixtures of the two was far greater than that found when either was used alone.
m. After the step of digestion with uricase, neither glucose nor uric acid reduced the reagent to form color.
Fig. 1 illustrates the effect of adding increasing amounts of glucose to a constant amount of uric acid. In urine which contains a normal amount of uric acid and a 4% glucose concentration, on proper dilution, the urine aliquot would give a reading about 80% higher than could be accounted for by the amount of uric acid alone, as that aliquot would contain 4 mg of glucose.
Further study of the uricase procedure disclosed that the loss of reducing action of glucose was due to the borate buffer. When a carbonate buffer was substituted for the borate in the uricase digestion, it was found that the reducing action due to glucose was not destroyed, indicating the hydrogen ion concentration was not a factor.
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