Wellik D M, DeLuca H F
Department of Biochemistry, University of Wisconsin at Madison 53706, USA.
Arch Biochem Biophys. 1996 Jun 15;330(2):355-62. doi: 10.1006/abbi.1996.0262.
It has been previously demonstrated that vitamin A-deficient rats supplemented with retinoic acid cannot complete gestation. Resorption of fetuses invariably occurs in these animals beginning Day 15 of gestation. Retinol must be administered on or before Day 10 of gestation in order to prevent this phenomenon. The administration of as little as 2 micrograms on Day 10 is sufficient to allow continuation of gestation through parturition. This study examines the metabolites of all-trans-retinol in the conceptuses of vitamin A-deficient, retinoic acid-supported pregnant animals at Day 10 of gestation. The retinoids recovered in this study could be identified as all-trans-retinol, retinyl palmitate, and other retinyl esters. Virtually no radiolabeled retinoic acid was found in the conceptuses of these animals over the 12-h period examined. This may suggest that retinoic acid that may be required by the fetus can arise directly from maternal sources. Additionally, the isolation of an early appearing, very polar metabolite of retinol is reported. This aqueous-soluble compound accounts for more than 20% of the radioactivity recovered at 1 h post-dose. The amount of this compound increases through 6 h post-dose. This metabolite is not found in urine from the same animals and is not likely to be an excretion product.
先前已经证明，补充视黄酸的维生素A缺乏大鼠无法完成妊娠。这些动物从妊娠第15天开始，胎儿必然会发生吸收。必须在妊娠第10天或之前给予视黄醇，以防止这种现象。在第10天给予低至2微克就足以使妊娠持续到分娩。本研究检测了维生素A缺乏、视黄酸支持的妊娠动物在妊娠第10天的胚胎中全反式视黄醇的代谢产物。本研究中回收的类视黄醇可鉴定为全反式视黄醇、棕榈酸视黄酯和其他视黄酯。在所检测的12小时内，在这些动物的胚胎中几乎未发现放射性标记的视黄酸。这可能表明胎儿所需的视黄酸可直接来自母体。此外，还报告了视黄醇一种早期出现的、极性很强的代谢产物的分离情况。这种水溶性化合物占给药后1小时回收放射性的20%以上。该化合物的量在给药后6小时内增加。在同一动物的尿液中未发现这种代谢产物，它不太可能是一种排泄产物。
