Urinary excretion of [2H4]folate by nonpregnant women following a single oral dose of [2H4]folic acid is a functional index of folate nutritional status
Urinary excretion of [2H4]folate by nonpregnant women following a single oral dose of [2H4]folic acid is a functional index of folate nutritional status
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DOI：
10.1093/jn/128.11.1907
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发表时间：
1998-11-01
影响因子：
4.2
通讯作者：
Toth, JP
中科院分区：
文献类型：
--
作者：
Gregory, JF;Williamson, J;Toth, JP
在一项为期10周的研究中，（21-27岁，每组n = 5-6），受试者被喂食含有类似于68 nmol/d（30 μ g/d）叶酸盐，来自于在苹果汁中补充叶酸的食物，以产生454、680或907 nmol/d的恒定摄入量（200、300或400 μ g/d）以评价叶酸状态和长期体内动力学。这里报告的是该方案的另一个阶段，以确定单次同位素标记剂量后短期尿排泄与叶酸营养状况的各种指标之间的关系。假设单次[谷氨酸-H-2（4）]叶酸（[H-2（4）]叶酸）给药的尿排泄量将与叶酸营养状态成比例增加，这是由于可饱和的细胞摄取和保留过程沿着肾脏重吸收饱和。每例受试者在研究第70天早晨口服1.13 μ mol（500 μ g）[H-2（4）]叶酸，随后收集24小时尿液。采用气相色谱-质谱联用（GC-MS）和高效液相色谱法（HPLC）分别测定尿中叶酸的同位素富集和浓度。尿中[H-2（4）]叶酸的排泄量在摄入量为907 nmol/d时最大，与血清叶酸浓度呈正相关，与红细胞叶酸浓度无相关性。当血浆同型半胱氨酸浓度低时，[H-2（4）]叶酸的排泄量最大（
In a 10-wk study with nonpregnant women (21-27 y, n = 5-6 per group), subjects were fed a diet containing similar to 68 nmol/d (30 mu g/d) folate from food that was supplemented with folic acid in apple juice to yield a constant intake of 454, 680 or 907 nmol/d (200, 300 or 400 mu g/d) to evaluate folate status and long-term in vivo kinetics. Reported here is an additional phase of this protocol conducted to determine the relationship between short-term urinary excretion after a single isotopically labeled dose and various measures of folate nutritional status. It was hypothesized that urinary excretion from a single [glutamate-H-2(4)]folic acid ([H-2(4)]folic acid) dose would increase in proportion to folate nutritional status due to saturable cellular uptake and retention processes along with saturation of renal reabsorption. Each subject was given 1.13 mu mol (500 mu g) of [H-2(4)]folic acid orally on the morning of d 70 of the study, followed by a complete 24-h urine collection. Urine was analyzed to determine the isotopic enrichment of urinary folate by gas chromatography-mass spectrometry and the concentration of urinary folate by HPLC, Urinary excretion of [H-2(4)]folate was greatest at the 907 nmol/d intake and was positively correlated with serum folate concentration but was not correlated with erythrocyte folate. Excretion of [H-2(4)]folate tended to be greatest when plasma homocysteine concentrations were low (