Muta K, Nishimura J, Ideguchi H, Umemura T, Ibayashi H
Am J Hematol. 1987 Jun;25(2):155-63. doi: 10.1002/ajh.2830250205.
To clarify the role of transferrin receptors in cases of altered iron metabolism in clinical pathological conditions, we studied: number of binding sites; affinity; and recycling kinetics of transferrin receptors on human erythroblasts. Since transferrin receptors are mainly present on erythroblasts, the number of surface transferrin receptors was determined by assay of binding of 125I-transferrin and the percentage of erythroblasts in bone marrow mononuclear cells. The number of binding sites on erythroblasts from patients with an iron deficiency anemia was significantly greater than in normal subjects (p less than 0.01). Among those with an aplastic anemia, hemolytic anemia, myelodysplastic syndrome, and polycythemia vera compared to normal subjects, there were no considerable differences in the numbers of binding sites. The dissociation constants (Kd) were measured using Scatchard analysis. The apparent Kd was unchanged (about 10 nmol/L) in patients and normal subjects. The kinetics of endocytosis and exocytosis of 125I-transferrin, examined by acid treatment, revealed no variations in recycling kinetics among the patients and normal subjects. These data suggest that iron uptake is regulated by modulation of the number of surface transferrin receptors, thereby reflecting the iron demand of the erythroblast.
为阐明转铁蛋白受体在临床病理状况下铁代谢改变病例中的作用，我们研究了：人成红细胞上转铁蛋白受体的结合位点数量、亲和力及再循环动力学。由于转铁蛋白受体主要存在于成红细胞上，因此通过检测¹²⁵I-转铁蛋白的结合情况以及骨髓单个核细胞中幼红细胞的百分比来确定表面转铁蛋白受体的数量。缺铁性贫血患者的成红细胞上的结合位点数量显著多于正常受试者（p < 0.01）。与正常受试者相比，再生障碍性贫血、溶血性贫血、骨髓增生异常综合征和真性红细胞增多症患者的结合位点数量没有显著差异。使用Scatchard分析测定解离常数（Kd）。患者和正常受试者的表观Kd没有变化（约10 nmol/L）。通过酸处理检测¹²⁵I-转铁蛋白的内吞和外排动力学，结果显示患者和正常受试者之间的再循环动力学没有差异。这些数据表明，铁摄取是通过调节表面转铁蛋白受体的数量来调控的，从而反映了成红细胞对铁的需求。
