CHROMOGRANIN-A SYNTHESIS AND SECRETION IN CHROMAFFIN CELLS
CHROMOGRANIN-A SYNTHESIS AND SECRETION IN CHROMAFFIN CELLS
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DOI：
10.1111/j.1471-4159.1987.tb03395.x
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发表时间：
1987-07-01
影响因子：
4.7
通讯作者：
AUNIS, D
中科院分区：
文献类型：
--
作者：
EIDEN, LE;IACANGELO, A;AUNIS, D
嗜铬粒蛋白A（chromogranin A，Chrg A）的放射免疫分析法可用于定量神经内分泌组织中该分泌蛋白的含量、释放和生物合成。从牛肾上腺髓质中提取的抗Chrg A的抗血清主要只检测到天然形式的Mr 70-75千道尔顿的Chrg A，允许使用这种抗血清作为肾上腺髓质和嗜铬细胞的无细胞提取物中Chrg A的定量特异性探针。Chrg A约占嗜铬细胞总蛋白的10%。在对尼古丁和烟碱胆碱能激动剂的反应中，它与甲硫氨酸脑啡肽和儿茶酚胺从原代培养的牛嗜铬细胞中平行释放。在暴露于最大刺激剂量的尼古丁（10-100 μ M）的5分钟期间，总Chrg A的14 - 22%从细胞释放。D-600和六烃季铵阻断烟碱刺激时的Chrg A释放的程度与Met-脑啡肽和儿茶酚胺释放的程度相同。Chrg A和Met-脑啡肽的平行时间过程和释放百分比表明这些分泌性多肽包含在功能相同的细胞隔室中并从其释放。Chrg A和Met-脑啡肽五肽序列以约2：1的比例存在于嗜铬细胞中，尽管Chrg A在质量基础上更丰富。Chrg A和Met-脑啡肽生物合成似乎在嗜铬细胞内受到差异调节，因为用尼古丁和毛喉素长期处理细胞导致Met-脑啡肽五肽升高，而不伴随细胞内Chrg A水平升高。
A sensitive and selective radioimmunoassay for chromogranin A (Chrg A) has been developed to quantitate content, release, and biosynthesis of this secretory protein in neuroendocrine tissues. An antiserum raised against Chrg A from bovine adrenal medulla was found to detect predominantly only the Mr 70-75 kilodalton Chrg A in its native form, allowing the use of this antiserum as a quantitatively specific probe for Chrg A in cell-free extracts of the adrenal medulla and chromaffin cells. Chrg A comprises about 10% of the total protein of the chromaffin cell. It is released in parallel with Met-enkephalin and catecholamines from the bovine chromaffin cell in primary culture in response to nicotine and nicotinic cholinergic agonists. From 14 to 22% of total Chrg A is released from the cell during a 5-min exposure to a maximally stimulatory dose of nicotine (10-100 .mu.M). Chrg A release on nicotinic stimulation is blocked by D-600 and hexamethonium to the same extent as Met-enkephalin and catecholamine release. The parallel time course and percent release of Chrg A and Met-enkephalin indicate that these secretory polypeptides are contained in, and released from, functionally identical cellular compartments. Chrg A and Met-enkephalin pentapeptide sequences are present in the chromaffin cell at a ratio of about 2:1 although Chrg A is far more abundant on a mass basis. Chrg A and Met-enkephalin biosynthesis appear to be differentially regulated within the chromaffin cell, since chronic treatment of cells with nicotine and forskolin causes an elevation of Met-enkephalin pentapeptide without a concomitant elevation of intracellular levels of Chrg A.