Document Detail

Effect of angiotensin II receptor blockade on proximal tubular fluid reabsorption.
MedLine Citation:
PMID:  9277533     Owner:  NLM     Status:  MEDLINE    
The effect of physiological concentrations of angiotensin II on proximal tubular fluid reabsorption remains controversial. To investigate the effect of blockade of intratubular AT1 receptors on tubular reabsorption, losartan (10(-5) M) was administered by microperfusion into an early proximal convolution of halothane-anesthetized Sprague-Dawley rats. Four parameters that depend on the rate of proximal fluid reabsorption were measured: proximal intratubular pressure (Pprox), early and late proximal flow rate, and early distal NaCl concentration. Pprox decreased by 0.5 +/- 0.1 mmHg, late proximal flow rate decreased by 2.0 +/- 0.8 nl/min, and early distal NaCl concentration decreased by 4.3 +/- 0.8 mM (mean +/- SE). No changes were observed after microperfusion with saline. Because the tubuloglomerular feedback mechanism was operating in the closed-loop mode, the decreased NaCl load to the macula densa will be compensated by an increase in the single-nephron glomerular filtration rate. In agreement with this, the early proximal flow rate, measured proximal to the site of losartan administration, increased by 5.7 +/- 1.3 nl/min. The increase in the rate of proximal reabsorption between the early and late proximal convolutions was estimated to be 7.8 nl/min (approximately 36%). It is concluded that a decrease in local luminal angiotensin II levels and/or AT1 receptor activity under free flow conditions increases the rate of proximal tubular fluid reabsorption.
P P Leyssac; F M Karlsen; N H Holstein-Rathlou
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of physiology     Volume:  273     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1997 Aug 
Date Detail:
Created Date:  1997-09-25     Completed Date:  1997-09-25     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  R510-7     Citation Subset:  IM    
Department of Medical Physiology, Panum Institute, University of Copenhagen, Denmark.
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MeSH Terms
Absorption / drug effects
Biphenyl Compounds / pharmacology
Body Fluids / metabolism*
Imidazoles / pharmacology
Kidney Tubules, Proximal / drug effects,  metabolism*,  physiology
Rats, Sprague-Dawley
Receptors, Angiotensin / antagonists & inhibitors*
Sodium Chloride / metabolism
Tetrazoles / pharmacology
Reg. No./Substance:
0/Biphenyl Compounds; 0/Imidazoles; 0/Receptors, Angiotensin; 0/Tetrazoles; 114798-26-4/Losartan; 7647-14-5/Sodium Chloride

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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