Sato M, DeLuca L M, Muto Y
J Nutr Sci Vitaminol (Tokyo). 1978;24(1):9-23. doi: 10.3177/jnsv.24.9.
Studies were conducted to investigate the in vivo and in vitro effects of retinol and retinoic acid on the synthesis of mannolipids and mannopeptides in rat liver. The incorporation of 14C-mannose into glycolipids and glycoproteins showed a decrease in vitamin A-depleted rats as compared with vitamin A-fed rats. By means of DEAE-cellulose, silicic acid and thin-layer chromatography, the mannose-containing lipids were separated into mannosyl retinyl phosphate (MRP, Rf 0.2) and dolichyl mannosyl phosphate (DMP, Rf 0.4), respectively. A rapid increase in the synthesis of labelled MRP was observed, exhibiting a peak between 25 and 60 min after intraperitoneal administration of retinol to vitamin A-depleted rats. Similarly, administration of retinoic acid brought about elevation of 14C-mannolipid (Rf 0.2) synthesis with a peak at 60 min after injection. On the other hand, the incorporation of 14C-mannose into DMP (Rf 0.4) remained unchanged by such treatment. In vitro addition of retinyl phosphate, but not retinoyl phosphate, markedly stimulated the synthesis of 14C-mannolipid (Rf 0.2), using crude membrane of rat liver and GDP-14C-mannose as the donor. These findings strongly suggest that not only retinol but also retinoic acid plays an important biological role in mannosyl transfer reaction in rat liver. However, the molecular participation of a metabolite of retinoic acid in the formation of a mannolipid and the structure of such a metabolite remain to be established.
开展了多项研究，以调查视黄醇和视黄酸对大鼠肝脏中甘露糖脂和甘露糖肽合成的体内和体外影响。与喂食维生素A的大鼠相比，维生素A缺乏的大鼠体内14C-甘露糖掺入糖脂和糖蛋白的量有所减少。通过DEAE-纤维素、硅酸和薄层色谱法，含甘露糖的脂质分别被分离为磷酸甘露糖视黄酯（MRP，Rf 0.2）和磷酸多萜醇甘露糖（DMP，Rf 0.4）。观察到标记的MRP合成迅速增加，在向维生素A缺乏的大鼠腹腔注射视黄醇后25至60分钟出现峰值。同样，注射视黄酸后，14C-甘露糖脂（Rf 0.2）的合成升高，在注射后60分钟达到峰值。另一方面，这种处理对14C-甘露糖掺入DMP（Rf 0.4）没有影响。在体外，以大鼠肝脏粗膜和GDP-14C-甘露糖作为供体，添加磷酸视黄酯而非磷酸视黄酰酯能显著刺激14C-甘露糖脂（Rf 0.2）的合成。这些发现有力地表明，视黄醇和视黄酸在大鼠肝脏的甘露糖基转移反应中都起着重要的生物学作用。然而，视黄酸代谢产物在甘露糖脂形成中的分子参与情况以及该代谢产物的结构仍有待确定。
