Cosecretion of atrial and brain natriuretic peptides stimulated by endothelin-1 from cultured rat atrial and ventricular cardiocytes.
We examined the secretion of immunoreactive (ir) atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in primary cultures of atrial and ventricular cardiocytes from neonatal rats, and also investigated the stimulatory effect of endothelin-1 (ET-1) on ir-ANP and ir-BNP release from these cells. After 2 days of culture, rat atrial and ventricular cardiocytes secreted both ir-ANP and ir-BNP into serum-free medium in a time-dependent manner. The amount of ir-BNP released per 10(5) ventricular cells was approximately 60% to 70% (1.8 +/- 0.5 pg/h, 2.5 +/- 0.4 pg/2 h, 2.6 +/- 0.4 pg/4 h) of that released from atrial cells (2.8 +/- 0.4 pg/h, 3.5 +/- 0.6 pg/2 h, 4.6 +/- 0.6 pg/4 h), although ir-ANP was secreted almost entirely from atrial cells. ET-1 clearly stimulated secretion of both ir-ANP and ir-BNP in atrial and ventricular cardiocytes. These observations indicate that ir-BNP is cosecreted with ir-ANP not only from atrial cardiocytes, but also from ventricular cardiocytes in the rat, and that ET-1 stimulates the secretion of these natriuretic peptides by a direct mechanism, not through a hemodynamic change.
Horio
T
T
First Department of Internal Medicine, Osaka City University Medical School, Japan.
Kohno
M
M
Takeda
T
T
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D002478:Cells, Cultured; D016232:Endothelins / Q000494:pharmacology*; D006325:Heart Atria; D006352:Heart Ventricles; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D020097:Natriuretic Peptide, Brain; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D051381:Rats; D013997:Time Factors
D016232:Endothelins; D009419:Nerve Tissue Proteins; D020097:Natriuretic Peptide, Brain; D009320:Atrial Natriuretic Factor