Question 9 of 16

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Which of the following would NOT be expected to contribute to hyperuricemia (gout)?

A. Unusually high levels of PRPP

B. Inhibition of xanthine oxidase

C. Unusually high turnover of nucleic acids

D. High activity of adenosine deaminase

E. Deficiency of HG-PRT

Comments:

Since the only control on uric acid synthesis is the availablility of substrates, anything which contributes to an increase in substrate concentration could lead to hyperuricemia. PRPP overcomes the normal feedback inhibition of synthesis. Both C and D would lead to more substrates. Since HG-PRT is an active consumer of PRPP and also the main salvage mechanism for both the guanine and adenine nucleotides, a deficiency would lead to high synthesis of nucleotides and, therefore, uric acid. An inhibitor of xanthine oxidase would specifically lower uric acid levels.

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Last modified 1/5/95