INTRACELLULAR-TRANSPORT AND PACKAGING OF PROLACTIN - QUANTITATIVE ELECTRON-MICROSCOPE AUTO-RADIOGRAPHIC STUDY OF MAMMOTROPHS DISSOCIATED FROM RAT PITUITARIES
INTRACELLULAR-TRANSPORT AND PACKAGING OF PROLACTIN - QUANTITATIVE ELECTRON-MICROSCOPE AUTO-RADIOGRAPHIC STUDY OF MAMMOTROPHS DISSOCIATED FROM RAT PITUITARIES
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DOI：
10.1210/endo-102-1-296
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发表时间：
1978-01-01
期刊：
影响因子：
4.8
通讯作者：
DANIELL, LW
中科院分区：
文献类型：
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作者：
FARQUHAR, MG;REID, JJ;DANIELL, LW
为研究催乳素(PRL)在乳腺滋养细胞内的转运，将雌性大鼠分散的垂体细胞用[~3H]亮氨酸脉冲标记(5min)，然后进行Chase孵育(最长3h)。用定量电子显微镜放射自显影测定了PRL的合成部位、转运速度、包装和储存部位。颗粒计数结果表明，标记物最初(脉冲末)随机分布在粗面内质网(ER)上，但迅速(追逐5-15分钟)移动到堆积的高尔基池，在那里集中进入分泌颗粒。在高尔基体区，标记从小的(I型)未成熟颗粒(追逐15-55min)到大的(II型和III型)多态颗粒(55-115min)，再到圆形或卵圆形的成熟(IV型)颗粒(55-185min)，表明这些类型的颗粒代表着颗粒聚集和组装的连续阶段。相对颗粒密度(占总颗粒的百分比/总面积百分比)的分析证实，沿运输路线存在着递增的浓度(最高可达20-150倍)，在内质网中浓度最低，在高尔基体中较高，在未成熟和成熟的分泌颗粒中最高。PRL的合成在内质网中随机发生，转运到高尔基体的速度很快(5-10分钟内)，并且完全迅速(15-20分钟内达到90%)，小颗粒的浓缩和聚集成较大的形式也迅速发生(15-20分钟)，但持续时间较长(长达3小时)。使用分散的细胞可以比以前使用其他系统更精确地确定PRL细胞内处理的步骤的位置和动力学。
Dispersed pituitary cells prepared from estrogen-treated female rats were subjected to pulse labeling with [3H]leucine (5 min) followed by a chase incubation (up to 3 h) in order to study intracellular transport of PRL in mammotrophs. Sites of synthesis, rates of transport, and sites of packaging and storage of PRL were determined by quantitative electron microscopic autoradiography. Results of grain counts show that label is initially (end of pulse) distributed randomly over the rough endoplasmic reticulum (ER), but rapidly (5-15 min of chase) moves to stacked Golgi cisternae where concentration into secretion granules takes place. The label moves successively from small (Type I) immature granules (15-55 min of chase) to large (Types II and III) polymorphic granules (55-115 min) in the Golgi region, to rounded or ovoid mature (Type IV) granules (55-185 min) usually found in the peripheral cytoplasm, indicating that these types of granules represent successive stages in granule concentration and assembly. Analysis of the relative grain density (percentage of total grains/percentage of total area) confirmed that there was progressive concentration (up to 20-150 times) along the transport route with the concentration lowest in the ER, higher in the Golgi, and highest in immature and mature secretion granules. Synthesis of PRL occurs randomly in the ER, transport to the Golgi occurs rapidly (within 5-10 min) and is completely rapidly (90% within 15-20 min), and concentration into granules and aggregation of small granules into larger forms also occurs rapidly (by 15-20 min), but goes on over a prolonged period of time (up to 3 h). Use of dispersed cells allowed a more precise determination of the location and kinetics of steps in the intracellular processing of PRL than was possible previously using other systems.