Document Detail

Determinants of the natriuresis after acute, slow sodium loading in conscious dogs.
MedLine Citation:
PMID:  10644615     Owner:  NLM     Status:  MEDLINE    
The relative importance of systemic volume, concentration, and pressure signals in sodium homeostasis was investigated by intravenous infusion of isotonic (IsoLoad) or hypertonic (HyperLoad) saline at a rate (1 micromol Na(+) x kg(-1) x s(-1)), similar to the rate of postprandial sodium absorption. IsoLoad decreased plasma vasopressin (-35%) and plasma ANG II (-77%) and increased renal sodium excretion (95-fold), arterial blood pressure (DeltaBP; +6 mmHg), and heart rate (HR; +36%). HyperLoad caused similar changes in plasma ANG II and sodium excretion, but augmented vasopressin (12-fold) and doubled DeltaBP (+12 mm Hg) without changing HR. IsoLoad during vasopressin clamping (constant vasopressin infusion) caused comparable natriuresis at augmented DeltaBP (+14 mm Hg), but constant HR. Thus vasopressin abolished the Bainbridge reflex. IsoLoad during normotensive angiotensin clamping (enalaprilate plus constant angiotensin infusion) caused marginal natriuresis (9% of unclamped response) despite augmented DeltaBP (+14 mm Hg). Cessation of angiotensin infusion during IsoLoad immediately decreased BP (-13 mm Hg) and increased glomerular filtration rate by 20% and sodium excretion by 45-fold. The results suggest that fading of ANG II is the cause of acute "volume-expansion" natriuresis, that physiological ANG II deviations override the effects of modest systemic blood pressure changes, and that endocrine rather than hemodynamic mechanisms are the pivot of normal sodium homeostasis.
P Bie; N C Sandgaard
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  278     ISSN:  0363-6119     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2000 Jan 
Date Detail:
Created Date:  2000-06-21     Completed Date:  2000-06-21     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  R1-R10     Citation Subset:  IM    
Department of Physiology and Pharmacology, University of Southern Denmark, Odense, DK-5000 Odense, Denmark.
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MeSH Terms
Angiotensin II / blood
Arginine Vasopressin / blood,  urine
Atrial Natriuretic Factor / blood
Blood Proteins / analysis
Diuresis / drug effects
Glomerular Filtration Rate / drug effects
Hemodynamics / drug effects
Injections, Intravenous
Isotonic Solutions / administration & dosage,  pharmacology
Natriuresis / drug effects*
Saline Solution, Hypertonic / administration & dosage,  pharmacology
Sodium / administration & dosage*,  pharmacology
Time Factors
Reg. No./Substance:
0/Blood Proteins; 0/Isotonic Solutions; 0/Saline Solution, Hypertonic; 11128-99-7/Angiotensin II; 113-79-1/Arginine Vasopressin; 7440-23-5/Sodium; 85637-73-6/Atrial Natriuretic Factor

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