MONITORING UREAGENESIS IN PATIENTS WITH OTC DEFICIENCY

我们开发了一种新的技术来监测雌性杂合子的代谢能力鸟氨酸转氨基甲酰基酶缺乏症（OTC）。我们的方法使用质谱法测量15NH4C1在口服15NH4C1 （25.9 mmol）后4小时内转化为（15N）尿素和（5-15N）谷氨酰胺。我们发现无症状的杂合子将较少的NH3氮转化为尿素。因此，症状型杂合子血中（15N）尿素浓度（mM）在大多数点显著低于对照值。无症状和有症状的杂合子血清（5-15N）谷氨酰胺（mM）浓度均显著高于对照组。给对照组注射试验剂量的苯丁酸钠不影响（15N）尿素的形成速率。

We have developed a novel technique for monitoring metabolic competency in female heterozygotes for ornithine transcarbamylase deficiency (OTC). Our method uses mass spectrometry to measure the conversion of 15NH4C1 to (15N) urea and (5-15N) glutamine during a 4 hour period following an oral 15NH4C1 load (25.9 mmol). We found that asymptomatic heterozygotes converted significantly less NH3 nitrogen to urea. Thus, the (15N) urea concentration (mM) in the blood of symptomatic heterzygotes was significantly less than control values at most points. The blood concentration of (5-15N) glutamine (mM) was significantly higher in both asymptomatic and symptomatic heterozygotes than it was in the control subjects. The administration of a test dose of sodium phenylbutyrate to the control group did not affect the rate of (15N) urea formation.