DOSE-DEPENDENT ABSORPTION AND EXCRETION OF VITAMIN-C IN HUMANS
DOSE-DEPENDENT ABSORPTION AND EXCRETION OF VITAMIN-C IN HUMANS
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DOI：
10.1016/0378-5173(86)90216-4
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发表时间：
1986-07-01
影响因子：
5.8
通讯作者：
CHANG, CJ
中科院分区：
文献类型：
--
作者：
MELETHIL, S;MASON, WD;CHANG, CJ
根据三向交叉设计，四名受试者每天摄入500、1000和2000 mg抗坏血酸，持续一周。末次给药后，在12小时内采集系列尿液和血浆样本。这些样品的抗坏血酸含量通过采用电化学检测的HPLC方法测定。在所有3个剂量下的血浆浓度-时间曲线相似，曲线下面积值（平均值± 0.00000）为0.0000000。标准差）为206.0 .+-。50.5，212.1 .+-。40.7和231.8 .+-。52.6 mg. cntdot。h/l（500、1000和2000 mg剂量）。相应的百分比（平均值±.标准差）尿中回收的剂量为73.2 ±。25.7，46.9 .+-. 21.7和35.8 . ±-。12.4.在500 mg剂量和两个更高剂量之间，这种恢复的降低显著不同（P < 0.05）。在研究中遇到的浓度范围（10-40 mg/l）内，肾清除率与血浆抗坏血酸成比例增加。本研究结果表明，维生素C的胃肠道吸收和肾小管重吸收均为饱和过程。因此，（1）使用线性药代动力学分析的既往研究的有效性和（2）口服大剂量维生素产生的全身效应值得商榷。
Four subjects ingested 500, 1000 and 2000 mg of ascorbic acid daily for one week according to a three-way crossover design. Following the last dose, serial urine and plasma samples were obtained over a 12-h period. The ascorbic acid content of these samples were determined by an HPLC method employing electrochemical detection. The plasma concentration-time profiles are similar at all 3 doses, with the area under the curve values (mean .+-. S.D.) being 206.0 .+-. 50.5, 212.1 .+-. 40.7, and 231.8 .+-. 52.6 mg .cntdot. h/l for the 500, 1000 and 2000 mg doses. The corresponding percents (mean .+-. S.D.) of dose recovered in urine are 73.2 .+-. 25.7, 46.9 .+-. 21.7 and 35.8 .+-. 12.4. This decrease in recovery is significantly different (P < 0.05) between the 500 mg dose and the two higher doses. Renal clearance increases in proportion to plasma ascorbic acid in the concentration range (10-40 mg/l) encountered in the study. Results from this study indicate that both gastrointestinal absorption and renal tubular reabsorption of vitamin C are saturable processes. Therefore, (1) the validity of previous studies which have used linear pharmacokinetic analyses and (2) the systemic effects to be derived from megadoses of the vitamin administered orally are open to question.