Gjøen T, Bjerkelund T, Blomhoff H K, Norum K R, Berg T, Blomhoff R
J Biol Chem. 1987 Aug 15;262(23):10926-30.
Retinol is transported in plasma bound to a specific transport protein, retinol-binding protein. We prepared 125I-tyramine cellobiose-labeled rat retinol-binding protein and studied its tissue uptake 1, 5, and 24 h after intravenous injection into rats. The liver was the organ containing most radioactivity at all time points studied. After 5 and 24 h, 30 and 22% of the injected dose were recovered in liver, respectively. After separating the liver into parenchymal and nonparenchymal cells in the 5-h group, we found that both cell fractions contained approximately the same amount of radioactivity (per gram of liver). Most of the retinol-binding protein radioactivity in the nonparenchymal cell fraction was in the stellate cells. The implication of these results for a possible transfer mechanism for retinol between parenchymal and stellate cells is discussed.
视黄醇在血浆中与一种特定的转运蛋白——视黄醇结合蛋白结合进行运输。我们制备了125I-酪胺纤维二糖标记的大鼠视黄醇结合蛋白，并在静脉注射给大鼠后1小时、5小时和24小时研究了其在组织中的摄取情况。在所研究的所有时间点，肝脏都是含有放射性最多的器官。5小时和24小时后，分别在肝脏中回收了30%和22%的注射剂量。在5小时组将肝脏分离为实质细胞和非实质细胞后，我们发现两个细胞组分中含有的放射性（每克肝脏）大致相同。非实质细胞组分中大部分视黄醇结合蛋白放射性存在于星状细胞中。讨论了这些结果对视黄醇在实质细胞和星状细胞之间可能的转运机制的意义。
