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Chromogranin A Synthesis and Secretion in Chromaffin Cells
Author(s) -
Eiden Lee E.,
Iacangelo Anna,
Hsu ChangMei,
Hotchkiss Adair J.,
Bader MarieFrance,
Aunis Dominique
Publication year - 1987
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1987.tb03395.x
Subject(s) - chromogranin a , secretion , chromaffin cell , endocrinology , medicine , chemistry , biology , adrenal medulla , catecholamine , immunohistochemistry
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 M r 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 catechol‐amines 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 15‐min exposure to a maximally stimulatory dose of nicotine (10–100 μ 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.