Premium
Increased Secretion of Adrenomedullin from Cultured Human Astrocytes by Cytokines
Author(s) -
Takahashi Kazuhiro,
Nakayama Masaharu,
Totsune Kazuhito,
Murakami Osamu,
Sone Masahiko,
Kitamuro Tomomi,
Yoshinoya Ayako,
Shibahara Shigeki
Publication year - 2000
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 - 10.1046/j.1471-4159.2000.0740099.x
Subject(s) - adrenomedullin , northern blot , endocrinology , secretion , western blot , medicine , tumor necrosis factor alpha , biology , radioimmunoassay , cytokine , interleukin , microbiology and biotechnology , chemistry , messenger rna , biochemistry , gene , receptor
Adrenomedullin, originally discovered from pheochromocytoma, is a member of the calcitonin gene‐related peptide family. The production and secretion of adrenomedullin by cultured human astrocytes were studied by northern blot analysis and radioimmunoassay. Northern blot analysis showed the expression of adrenomedullin mRNA in cultured human astrocytes. Immunoreactive adrenomedullin concentrations in the culture medium were 29.6 ± 1.2 fmol/10 5 cells/24 h (mean ± SEM, n = 4). Treatment with interferon‐γ (100 U/ml), tumor necrosis factor‐α (1 and 10 ng/ml), or interleukin‐1β (1 and 10 ng/ml) for 24 h caused >20‐fold increases in immunoreactive adrenomedullin levels in the culture medium of human astrocytes. On the other hand, northern blot analysis showed only small increases (∼40%) in the adrenomedullin mRNA expression of human astrocytes with either 100 U/ml interferon‐γ or 10 ng/ml interleukin‐1β and no noticeable change with tumor necrosis factor‐α. Reverse phase HPLC of the medium extracts of human astrocytes treated with interferon‐γ, tumor necrosis factor‐α, or interleukin‐1β showed that most of immunoreactive adrenomedullin was eluted in the position of adrenomedullin‐(1‐52). On the other hand, immunoreactive adrenomedullin in the medium of human astrocytes without cytokine treatment was eluted earlier than the adrenomedullin standard, suggesting that this immunoreactive adrenomedullin represents adrenomedullin with some modifications or fragments of the adrenomedullin precursor. The present study has shown the production and secretion of adrenomedullin by human astrocytes and increased secretion of adrenomedullin by cytokines.