Beta granule formation in isolated islets of langerhans: a study by electron microscopic radioautography.
Beta granule formation in isolated islets of langerhans: a study by electron microscopic radioautography.
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DOI：
10.1083/jcb.42.3.695
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发表时间：
1969-09
期刊：
影响因子：
--
通讯作者：
Lacy PE
中科院分区：
文献类型：
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作者：
Howell SL;Kostianovsky M;Lacy PE
用氚标记氨基酸对大鼠朗格汉斯胰岛进行脉冲标记后，在不同时间对胰岛细胞器上放射自显影颗粒的分布进行了研究。标记开始10分钟后，大部分颗粒位于内质网和细胞质上；相比之下，从标记开始60分钟后，大多数颗粒与β颗粒相关。在脉冲标记后20,30和45分钟，与高尔基体相关的谷物比例比10分钟或60分钟的值增加了两到三倍。完整细胞中放射自显影颗粒在颗粒上的分布并不表明电子透明型分泌颗粒是电子不透明颗粒的前体。此外，对脉冲标记后60分钟离心分离的颗粒上颗粒模式的研究表明，电子朗讯型颗粒没有优先标记。由此得出结论，标记的氨基酸最初在内质网中结合，随后在β颗粒中出现标记。高尔基复合体参与β颗粒的形成或参与β颗粒通过细胞质的转运。
The distribution of radioautographic grains over organelles within the beta cells of rat islets of Langerhans was investigated at various times after pulse labeling of the isolated islets with tritium-labeled amino acids. Ten minutes after the start of labeling most of the grains were situated over the endoplasmic reticulum and cytoplasm; by contrast, 60 min from the start of labeling the majority of the grains were associated with the beta granules. At 20, 30, and 45 minutes after pulse labeling the proportion of grains associated with the Golgi complex was increased two- to three-fold over the 10- or 60-minute values. The distribution of radioautographic grains over granules in the intact cells did not suggest that the electron-lucent type of secretory granules were precursors of the electron-opaque granules. Furthermore, studies of the pattern of grains over granules isolated by centrifugation 60 min after pulse labeling showed no preferential labeling of the electron-lucent type of granule. It is concluded that labeled amino acids are incorporated initially in the endoplasmic reticulum, and that the label subsequently appears in the beta granules. The Golgi complex participates either in the formation of the beta granule or in the translocation of the granule through the cytoplasm of the cell.