Fate of [125I]angiotensin II in adrenal zona glomerulosa cells.
Fate of [125I]angiotensin II in adrenal zona glomerulosa cells.
复制标题
[125I]血管紧张素 II 在肾上腺肾小球带细胞中的命运。
作者：
C. Bianchi;J. Gutkowska;A. De Léan;M. Ballak;M. Anand;J. Genest;M. Cantin
用形态学和生物化学方法研究了大鼠体内[125I]血管紧张素II（AII）的结合和内化。光镜放射自显影显示[125 I]AII特异性结合于肾上腺肾小球（ZG）细胞。超微结构放射自显影分析显示，[125 I]AII结合到细胞表面，集群在包被的坑，是内在的包被囊泡，并在不到20分钟的时间内由受体体运输到溶酶体。生化分析显示，多达40%的肾上腺放射性摄取的行为作为本地[125 I]AII所示的电泳，免疫沉淀和放射性配体结合研究。这些结果表明AII对ZG细胞分泌醛固酮的影响是由细胞表面现象介导的，而不是通过与参与类固醇生成的细胞内细胞器结合。它们还表明，与受体结合并内化的AII的半衰期（min）似乎比体循环中的半衰期（sec）长得多。
Binding and internalization of [125I]angiotensin II (AII) were studied by morphological and biochemical methods in rats in vivo. Light microscope radioautography demonstrated that [125I]AII binds specifically to adrenal zona glomerulosa (ZG) cells. Ultrastructural radioautographic analysis revealed that [125I]AII binds to the cell surface, clusters in coated pits, is internalized in coated vesicles, and is transported by receptosomes to lysosomes in less than 20 min. Biochemical analysis revealed that as much as 40% of the adrenal radioactive uptake behaves as native [125I]AII as shown by electrophoresis, immunoprecipitation and radioligand binding studies. These results indicate that the effects of AII on the secretion of aldosterone by ZG cells are mediated by cell surface phenomena and not by binding to intracellular organelles involved in steroidogenesis. They also indicate that the half-life of AII bound to receptors and internalized seems to be much longer (min) than in the systemic circulation (sec).