Mateos F A, Puig J G, Jiménez M L, Fox I H
J Clin Invest. 1987 Mar;79(3):847-52. doi: 10.1172/JCI112893.
We tested the hypothesis that there is an enhanced rate of hypoxanthine salvage in two siblings with hereditary xanthinuria. We radiolabeled the adenine nucleotide pool with [8-14C]adenine and examined purine nucleotide degradation after intravenous fructose. The cumulative excretion of radioactivity during a 5-d period was 9.7% and 9.1% of infused radioactivity in the enzyme-deficient patients and 6.0 +/- 0.7% (mean +/- SE) in four normal subjects. Fructose infusion increased urinary radioactivity to 7.96 and 9.16 X 10(6) cpm/g creatinine in both patients and to 4.73 +/- 0.69 X 10(6) cpm/g creatinine in controls. The infusion of fructose increased total urinary purine excretion to a mean of 487% from low-normal baseline values in the patients and to 398 +/- 86% in control subjects. In the enzyme-deficient patients, the infusion of fructose elicited an increase of plasma guanosine from undetectable values to 0.7 and 0.9 microM. With adjustments made for intestinal purine loss, these data support the hypothesis that there is enhanced hypoxanthine salvage in hereditary xanthinuria. Degradation of guanine nucleotides to xanthine bypasses the hypoxanthine salvage pathway and may explain the predominance of this urinary purine compound in xanthinuria.
在两名患有遗传性黄嘌呤尿症的兄弟姐妹中，次黄嘌呤补救率有所提高。我们用[8-14C]腺嘌呤对腺嘌呤核苷酸池进行放射性标记，并在静脉注射果糖后检查嘌呤核苷酸的降解情况。在5天的时间段内，酶缺乏患者放射性的累积排泄量分别为注入放射性的9.7%和9.1%，而四名正常受试者为6.0±0.7%（平均值±标准误）。果糖输注使两名患者的尿放射性分别增加至7.96和9.16×10(6) cpm/g肌酐，对照组增加至4.73±0.69×10(6) cpm/g肌酐。果糖输注使患者的尿嘌呤总排泄量从低正常基线值平均增加至487%，对照组增加至398±86%。在酶缺乏患者中，果糖输注使血浆鸟苷从检测不到的值增加至0.7和0.9微摩尔。在对肠道嘌呤损失进行校正后，这些数据支持了遗传性黄嘌呤尿症中次黄嘌呤补救增强的假设。鸟嘌呤核苷酸降解为黄嘌呤绕过了次黄嘌呤补救途径，这可能解释了黄嘌呤尿症中这种尿嘌呤化合物占优势的原因。
