A role for atrial natriuretic peptide in endothelin-induced natriuresis.
Systemic administration of low-dose endothelin increases urinary sodium excretion rate despite mild to moderate reductions in renal plasma flow and glomerular filtration rates. The role of atrial natriuretic peptide in endothelin-induced natriuresis was investigated. Administration of 2.50 pmol/min of endothelin to euvolemic rats resulted in increases in plasma atrial natriuretic peptide levels from 127 +/- 18 to 169 +/- 23 pg/mL. However, a lower dose of endothelin (0.63 pmol/min) or saline did not increase plasma levels of atrial natriuretic peptide. Mean arterial pressure was unchanged at the lower dose of endothelin and increased only slightly in rats receiving 2.5 pmol/min. To assess functional significance, renal responses to endothelin (2.5 pmol/min) in the absence and presence of a specific anti-rat atrial natriuretic peptide antibody were compared. Equivalent reductions in renal blood flow were observed. Urinary sodium excretion rates increased significantly in non-ANP-antibody-treated rats by 33 +/- 7 and 82 +/- 20% at 10 and 30 min, respectively. Atrial natriuretic peptide antibody blunted markedly endothelin-induced natriuresis: urinary sodium excretion rates changed insignificantly by 18 +/- 10 and 30 +/- 14%, respectively. Thus, endothelin infusion results in increases in plasma atrial natriuretic peptide levels, which may contribute to endothelin-induced natriuresis, providing evidence for potentially significant interactions between these peptide hormones in the regulation of sodium balance and renal vascular tone.
Munger
K A
KA
Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-2372.
Sugiura
M
M
Takahashi
K
K
Inagami
T
T
Badr
K F
KF
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000097:blood / Q000502:physiology*; D001794:Blood Pressure / Q000187:drug effects; D016232:Endothelins / Q000008:administration & dosage / Q000494:pharmacology*; D005919:Glomerular Filtration Rate / Q000187:drug effects; D008297:Male; D009318:Natriuresis / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D012079:Renal Circulation / Q000187:drug effects
D016232:Endothelins; D009320:Atrial Natriuretic Factor