Eckhoff C, Nau H
Institut für Toxikologie und Embryonalpharmakologie, Freie Universität Berlin, West Germany.
J Lipid Res. 1990 Aug;31(8):1445-54.
Human plasma was analyzed by high performance liquid chromatography for the presence of retinoic acid and 4-oxoretinoic acid isomers. Peaks that coeluted with the reference compounds all-trans-retinoic acid, 13-cis-retinoic acid, and 13-cis-4-oxoretinoic acid were routinely observed in human plasma. These retinoids were unequivocally identified by the following methods: comigration with reference compounds under several high performance liquid chromatographic conditions; comparison of ultraviolet spectra with those of reference compounds; derivatization with diazomethane and coelution of the methyl esters with reference compounds in a high performance liquid chromatographic system as well as in a gas chromatography system with a mass selective detector. In vitro formation of 13-cis-retinoic acid and 13-cis-4-oxoretinoic acid as artifacts during the analytical procedure was excluded by control experiments. The mean plasma concentrations of the vitamin A metabolites in ten male volunteers were: all-trans-retinoic acid: 1.32 +/- 0.46 ng/ml; 13-cis-retinoic acid: 1.63 +/- 0.85 ng/ml; and 13-cis-4-oxoretinoic acid: 3.68 +/- 0.99 ng/ml. After oral dosing with vitamin A (833 IU/kg body weight) in five male volunteers, mean plasma all-trans-retinoic acid increased to 3.92 +/- 1.40 ng/ml and 13-cis-retinoic acid increased to 9.75 +/- 2.18 ng/ml. Maximal plasma 13-cis-4-oxoretinoic acid concentrations (average 7.60 +/- 1.45 ng/ml) were observed 6 h after dosing which was the last time point in this study. Concentrations of all-trans-4-oxoretinoic acid were low or not detectable. Our findings suggest that, in addition to all-trans-retinoic acid, 13-cis-retinoic acid and 13-cis-4-oxoretinoic acid are present in normal human plasma as metabolites of vitamin A.
采用高效液相色谱法分析人血浆中视黄酸和4-氧代视黄酸异构体的存在情况。在人血浆中经常观察到与参考化合物全反式视黄酸、13-顺式视黄酸和13-顺式-4-氧代视黄酸共洗脱的峰。这些类视黄醇通过以下方法明确鉴定：在几种高效液相色谱条件下与参考化合物共迁移；将紫外光谱与参考化合物的紫外光谱进行比较；用重氮甲烷衍生化，并在高效液相色谱系统以及配备质量选择检测器的气相色谱系统中使甲酯与参考化合物共洗脱。通过对照实验排除了分析过程中作为假象的13-顺式视黄酸和13-顺式-4-氧代视黄酸的体外形成。10名男性志愿者血浆中维生素A代谢物的平均浓度为：全反式视黄酸：1.32±0.46 ng/ml；13-顺式视黄酸：1.63±0.85 ng/ml；13-顺式-4-氧代视黄酸：3.68±0.99 ng/ml。5名男性志愿者口服维生素A（833 IU/kg体重）后，血浆中全反式视黄酸的平均浓度升至3.92±1.40 ng/ml，13-顺式视黄酸升至9.75±2.18 ng/ml。给药后6小时观察到血浆中13-顺式-4-氧代视黄酸的最大浓度（平均7.60±1.45 ng/ml），这是本研究中的最后一个时间点。全反式-4-氧代视黄酸的浓度较低或无法检测到。我们的研究结果表明，除全反式视黄酸外，13-顺式视黄酸和13-顺式-4-氧代视黄酸作为维生素A的代谢物存在于正常人血浆中。
