Document Detail


Amino acids induce renal vasodilatation in isolated perfused kidney: coupling to oxidative metabolism.
MedLine Citation:
PMID:  6507648     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Renal vasodilatation regularly accompanies protein feeding and amino acid infusions, but the mechanism is unknown. The effects of several different amino acids on renal hemodynamics were studied in the isolated rat kidney, perfused with glucose as the only other substrate. Addition of amino acids produced a dose-dependent, brisk, and sustained decrease in renal vascular resistance (by 5-35%) without change in glomerular filtration rate (GFR). The vasodilatation was associated with a parallel increase in O2 consumption (increases QO2). The effect was most marked with amino acids actively metabolized by the kidney, such as glutamine (at 2 mM), but was seen with most amino acids at 8 mM. The amino acid analogues alpha-aminobutyrate, taurine, and cycloleucine, cotransported with sodium but not metabolized, did not cause significant vasodilatation or increases QO2. Blocking active transport with ouabain blunted the amino acid-induced vasodilatation and increases QO2. Similar resistance to amino acids was produced by halting GFR with hyperoncotic medium. Restoration of GFR by increasing perfusion pressure in the presence of hyperoncotic medium reestablished amino acid-induced vasodilatation and increases QO2. Furosemide did not block the vasodilatory response. Inhibition of mitochondrial respiration by antimycin blocked both vasodilatation and increases QO2, but rotenone blockade could be bypassed by succinate or glutamine. Amino acids have a direct vasodilating action on isolated kidneys probably related to their role as metabolic substrates and linked to an increase in renal O2 consumption.
Authors:
M Brezis; P Silva; F H Epstein
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Publication Detail:
Type:  Comparative Study; In Vitro; Journal Article    
Journal Detail:
Title:  The American journal of physiology     Volume:  247     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1984 Dec 
Date Detail:
Created Date:  1985-01-24     Completed Date:  1985-01-24     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:  H999-1004     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Amino Acids / pharmacology*
Animals
Biological Transport, Active
Kidney / metabolism*
Male
Mitochondria / metabolism
Oxidation-Reduction
Oxygen Consumption
Perfusion
Rats
Rats, Inbred Strains
Renal Circulation / drug effects*
Vascular Resistance / drug effects
Vasodilation / drug effects*
Chemical
Reg. No./Substance:
0/Amino Acids

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


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