VITAMIN B6 DEPLETION IN MAN - URINARY EXCRETION OF QUINOLINIC ACID AND NIACIN METABOLITES
VITAMIN B6 DEPLETION IN MAN - URINARY EXCRETION OF QUINOLINIC ACID AND NIACIN METABOLITES
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DOI：
10.1093/jn/87.4.419
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发表时间：
1965-01-01
影响因子：
4.2
通讯作者：
HANKES, LV
中科院分区：
文献类型：
--
作者：
BROWN, RR;YESS, N;HANKES, LV
在一项为期 55 天的实验中，研究了 6 名男性受试者缺乏维生素 Bg 对色氨酸转化为烟酸的影响。在受试者自行选择饮食的5天预消耗期内，测量喹啉酸、烟酸、N1-甲基烟酰胺和N-甲基-2-吡啶酮-5-甲酰胺的尿排泄量；当他们每日摄入仅含 0.16 毫克维生素 Bg 的饮食时，当他们每天补充 0.6 或 0.9 毫克吡哆醇的饮食时，在消耗期间；当他们每天接受 50 毫克吡哆醇时。在每个时期加载 2 g L-色氨酸之前和之后测定 4 种代谢物的尿水平。在维生素 Bg 消耗期间，色氨酸后喹啉酸排泄水平和产量（色氨酸后值减去基础值）显着升高，并且在用吡哆醇补充和饱和后，这些水平和产量恢复到消耗前水平。在消耗高峰期间，N1-甲基烟酰胺值与补充或饱和期间的值没有显着差异，但与消耗前值不同，可能是因为受试者在消耗前期间吃的是自行选择的饮食。其他时期4种代谢物的排泄水平无统计学差异。该实验的结果表明喹啉酸的代谢可能需要维生素 B6 辅酶。
The effect of vitamin Bg depletion on the conversion of tryptophan to niacin by 6 male subjects was studied during a 55-day experiment. The urinary excretion of quinolinic acid, nicotinic acid, N1-methylnicotinamide and N-methyl-2-pyridone-5-carboxamide was measured during a 5-day pre-depletion period when the subjects ate self-selected diets; during depletion while they consumed a diet containing only 0.16 mg of vitamin Bg daily, when they were fed diets supplemented with 0.6 or 0.9 mg of pyridoxine/day; and when they received 50 mg of pyridoxine daily. The urinary levels of the 4 metabolites were determined before and after loading with 2 g of L-tryptophan during each of these periods. Post-tryptophan quinolinic acid excretion levels and yields (post-tryptophan values minus basal values) were significantly elevated during vitamin Bg depletion and these returned to pre-depletion levels upon repletion and saturation with pyridoxine. During the height of depletion, N1-methyl-nicotinamide values were not significantly different from values during repletion or saturation but differed from pre-depletion values probably because the subjects were eating self-selected diets during the pre-depletion period. The excretion levels of the 4 metabolites in other periods were not statistically different. The results of this experiment suggest a possible requirement for vitamin B6 coenzymes in the metabolism of quinolinic acid.