Purine metabolism in high and low uric acid lines of chickens: de novo uric acid synthesis in isolated hepatocytes and phosphoribosylpyrophosphate amidotransferase activities.

The de novo biosynthesis of uric acid was examined in isolated hepatocytes from the high and low uric acid lines of chickens. Rates of incorporation of radiolabeled glycine into uric acid by hepatocytes from the high uric acid (HUA) line were approximately 3.6-fold greater than found in low uric acid (LUA) control hepatocytes. Uric acid synthesis rates in these cells were positively correlated with plasma uric acid levels (r = +0.77; P less than 0.01). The activity of phosphoribosylpyrophosphate (PRPP) amidotransferase was measured in acetone powder preparations from liver and kidney tissues of the HUA and LUA lines. Activities in kidney tissues were about 21% lower than those found in livers. PRPP amidotransferase activities in liver and kidney tissues did not correlate significantly with plasma uric acid levels. The increased synthesis of uric acid in the HUA line may be the result of the increased PRPP synthetase activities and PRPP pool sizes previously reported for these tissues.