Open AccessCyclic AMP‐dependent synthesis and release of adrenomedullin and proadrenomedullin N‐terminal 20 peptide in cultured bovine adrenal chromaffin cells
Author(s) -
Kobayashi Hideyuki,
Yamamoto Ryuichi,
Kitamura Kazuo,
Niina Hiromi,
Masumoto Keizo,
Minami Shinichi,
Yanagita Toshihiko,
Izumi Futoshi,
Aunis Dominique,
Eto Tanenao,
Wada Akihiko
Publication year - 1999
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.1999.00546.x
Subject(s) - adrenomedullin , medicine , endocrinology , protein kinase a , peptide , chromaffin cell , extracellular , chromogranin a , chemistry , messenger rna , adrenal medulla , kinase , biology , biochemistry , catecholamine , gene , immunohistochemistry
Adrenomedullin and proadrenomedullin N‐terminal 20 peptide are peptides with multiple physiological functions and are most abundant in adrenal medulla. We studied whether the cAMP‐dependent pathway is involved in the regulation of synthesis and release of adrenomedullin and proadrenomedullin N‐terminal 20 peptide in cultured bovine adrenal chromaffin cells. Exposure of the cells to dibutyryl cAMP (dbcAMP) increased a progressive accumulation of immunoreactive‐adrenomedullin and immunoreactive‐proadrenomedullin N‐terminal 20 peptide in the extracellular medium, while reciprocally decreasing their cellular content in a time‐dependent manner. The decrease of levels of both peptides in the cells was much greater in extent than the increase of the peptides in the medium. H89, an inhibitor of cAMP‐dependent protein kinase attenuated these changes, induced by dbcAMP. The resulting changes by dbcAMP and H89 were similar to those of chromogranin B, a marker peptide of chromaffin granule. Northern blot analysis showed that the mRNA encoding these peptides, detected as a band of 1.6 kb, was decreased by the treatment with dbcAMP. The effect of dbcAMP on mRNA was attenuated by H89, and was reversible as the decreased mRNA level caused by dbcAMP could be returned to control levels by culturing cells after removal of dbcAMP. These results suggest that the cAMP‐dependent protein kinase pathway stimulates the release of adrenomedullin and proadrenomedullin N‐terminal 20 peptide, whereas it lowers synthesis of these peptides via the reduction of their transcript level.