Linked Life Data

10362678

Source:http://linkedlifedata.com/resource/pubmed/id/10362678

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6 Pt 2
pubmed:dateCreated
1999-7-22
pubmed:abstractText
The cardiac polypeptide hormones atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP) are synthesized and costored by atrial cardiocytes and share receptors and many biologic properties. Although some aspects of their synthesis and release are specific for each peptide, it is not clear whether they share intracellular sorting and secretory mechanisms. In the present work we take advantage of a stable isolated rat atrial preparation that allows, for the first time, long-term study of synthesis, trafficking, targeting, and secretion of ANF and BNP by adult atrial muscle. Three model stimuli of secretion were used: increased intra-atrial pressure, endothelin-1 (ET-1), and phenylephrine (PE), representing mechanical, hormonal, and alpha1-adrenergic stimuli, respectively. To gain further insight into the secretory process under basal and agonist-induced secretion, we employed agents known to inhibit protein synthesis (cycloheximide) or to interfere with the vectorial transport of protein targeted for secretion (brefeldin A and monensin). All these agents induced significant changes in ANF and BNP release. Cycloheximide decreased natriuretic peptide secretion under basal and stimulated conditions. Brefeldin A dramatically increased basal as well as stimulated secretion of ANF and BNP. Monensin partially decreased basal ANF and BNP secretion and completely blocked stimulated secretion. None of these agents modified proteolytic processing as assessed by reverse-phase HPLC analysis. Double-label pulse-chase experiments using [3H]- and [14C]leucine demonstrated that the secretory response to ET-1, in contrast to the response to muscle stretch, is based on peptide other than newly synthesized or relatively newly stored ANF. It is concluded that, in adult atrial cardiocytes, ANF and BNP are sorted to constitutive and regulated pathways in a manner that is substantially unique for atrial cardiocytes. In particular, it appears that basal and stimulated ANF and BNP secretion may have a large "constitutive-like" component, as previously defined in other endocrine systems. This type of secretion is based on the preferential release of hormone through vesicles arising from immature secretory granules. The capacity of the atria to release ANF and BNP in response to stimuli, therefore, may depend more on stimulation of the rate of formation of immature granules than on the amount of stored hormone.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0002-9513
pubmed:author
pubmed:issnType
Print
pubmed:volume
276
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
H1977-86
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Characterization of natriuretic peptide production by adult heart atria.
pubmed:affiliation
Cardiac Cell and Molecular Biology Laboratory, University of Ottawa Heart Institute at the Ottawa Hospital, Ottawa, Ontario, Canada K1Y 4W7.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't