Samezima K, Orii H
Eur J Nucl Med. 1980 Jun;5(3):281-8. doi: 10.1007/BF00271913.
The in vivo behaviour of Ga-67 citrate was studied, using a rat liver model, and the mechanisms of cellular uptake were investigated by observing the time course of the radionuclide in subcellular liver cell fractions. Modified continuous ultracentrifugation was used to successively fractionate the homogenates according to isopycnic and rate-zonal principles. To collect the cell nuclei, a special technique, which consisted of supplementing the outer sucrose layer with cesium chloride to increase density, was applied to trap nuclei with isopycnic equilibrium. We isolated nuclei, mitchondria, lysosomes and peroxysomes, microsomes, and the cell supernatant in a sufficiently purified state. By this method, the in vivo localization of Ga-67 was studied. At 30 min after intravenous injection, radioactivity was found mainly in the cell supernatant, the radioactivity peak corresponded to 5 S. However, after 24 h, the radioactivity was localized in the heavier fraction containing lysosomes and heavy endoplasmic reticulum. No intranuclear localization was observed. In spite of the difficulty in completely separating the lysosomal fraction from heavy endoplasmic reticulum, our results suggest the participation of heavy endoplasmic reticulum in gallium localization.
利用大鼠肝脏模型研究了柠檬酸镓-67的体内行为，并通过观察放射性核素在亚细胞肝细胞组分中的时间进程来研究细胞摄取机制。采用改良的连续超速离心法，根据等密度和速率区带原理对匀浆进行连续分级分离。为了收集细胞核，应用了一种特殊技术，即在外部蔗糖层中添加氯化铯以增加密度，通过等密度平衡来捕获细胞核。我们以足够纯净的状态分离出了细胞核、线粒体、溶酶体和过氧化物酶体、微粒体以及细胞上清液。通过这种方法，研究了镓-67在体内的定位。静脉注射后30分钟，放射性主要存在于细胞上清液中，放射性峰值对应于5S。然而，24小时后，放射性定位在含有溶酶体和粗面内质网的较重组分中。未观察到核内定位。尽管很难将溶酶体组分与粗面内质网完全分离，但我们的结果表明粗面内质网参与了镓的定位。
