Désormeaux Y, Ballak M, Benchimol S, Lacasse J, Cantin M, Genest J
Cell Tissue Res. 1982;222(1):53-67. doi: 10.1007/BF00218288.
Sections of juxtaglomerular cells from sodium-deficient rats were subjected to radioautography after a single intravenous injection of L-tyrosine-3,5 3H or of L-fucose 3H to identify the sites of synthesis and to follow the migration of newly-formed proteins and glycoproteins. As early as 2 min after injection of L-tyrosine 3H, the label was highest in the rough endoplasmic reticulum (RER), suggesting that cisternal ribosomes are sites of protein synthesis. By 60 min, much of the label had migrated from the RER to the Golgi complex. Some radioactivity was already present over specific granules by 2 min but a peak was reached at 4 h. The label over myofilaments was evident at all time intervals, indicating a certain incorporation of tyrosine into their contractile and/or structural proteins. The label over the cell surface peaked at 4 h. After injection of L-fucose 3H, there was an early and important relative specific radioactivity in the Golgi complex at 5 min with a peak at 20 min and a decrease thereafter. The label increased slightly but steadily in secretory granules and cell surface to reach maxima at 4 h. A low level of radioactivity was recorded in mitochondria at all time intervals. After injection of both fucose 3H and tyrosine 3H, the label was detected at relatively low levels in the cytosol. These results suggest that renin, as the major secretory glycoprotein of juxtaglomerular cells, is synthetized in the RER, packaged in the Golgi complex and found relatively rapidly in newly-formed secretory granules. Part of the fucose and tyrosine labels is also associated with the thick cell coat of these cells.
给缺钠大鼠的近球细胞切片单次静脉注射L-酪氨酸-3,5³H或L-岩藻糖³H后，进行放射自显影，以确定合成部位，并追踪新形成的蛋白质和糖蛋白的迁移情况。注射L-酪氨酸³H后2分钟，标记物在粗面内质网（RER）中含量最高，这表明池核糖体是蛋白质合成的部位。到60分钟时，大部分标记物已从RER迁移到高尔基体复合体。2分钟时，一些放射性已经出现在特定颗粒上，但在4小时时达到峰值。在所有时间间隔内，肌丝上的标记物都很明显，这表明酪氨酸一定掺入了它们的收缩和/或结构蛋白中。细胞表面的标记物在4小时时达到峰值。注射L-岩藻糖³H后，高尔基体复合体在5分钟时出现早期且重要的相对比放射性，在20分钟时达到峰值，此后下降。标记物在分泌颗粒和细胞表面略有但稳定地增加，在4小时时达到最大值。在所有时间间隔内，线粒体中的放射性水平都很低。注射L-岩藻糖³H和L-酪氨酸³H后，在细胞质中检测到相对较低水平的标记物。这些结果表明，肾素作为近球细胞的主要分泌糖蛋白，在RER中合成，在高尔基体复合体中包装，并相对迅速地出现在新形成的分泌颗粒中。部分岩藻糖和酪氨酸标记物也与这些细胞的厚细胞被相关。
