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Title: Mechanisms controlling renal hemodynamics and electrolyte excretion during amino acids

Abstract

Our purpose was to investigate the mechanisms by which increased plasma amino acids elevate renal blood flow (RBF) and glomerular filtration rate (GFR). Since transport of amino acids and Na is linked in the proximal tubule, the authors hypothesized that increased amino acids might stimulate proximal tubular Na reabsorption (PR/sub Na/) and thus increase RBF and GFR by a macula densa feedback mechanism. A solution of four amino acids (Ala, Ser, Gly, Pro) was infused intravenously into anesthetized dogs with normal kidneys (NK) and with kidneys in which the tubuloglomerular feedback mechanism was blunted by lowering renal artery pressure (LPK) or blocked by making the kidneys nonfiltering (NFK). In NK, RBF and GFR increased by 35 +/- 4% and 30 +/- 7% after 90 min of amino acid infusion, while PR/sub Na/ (estimated from lithium clearance) and O2 consumption increased by 31 +/- 5% and 29 +/- 5% and distal Na delivery remained relatively constant. Autoregulation of RBF and GFR in response to step deceases in renal artery pressure was impaired during amino acids in NK. The hemodynamic responses to amino acids were abolished in LPK and NFK. Infusion of the nonmetabolized -aminoisobutyric acid into NK produced changes in renalmore » hemodynamics that were similar to the responses observed with the four metabolizable amino acids. These data are consistent with the hypothesis that elevation of plasma amino acids increases RBF and GFR by a mechanism that requires an intact macula densa feedback. Metabolism of the amino acids does not appear to be necessary for these changes to occur.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Univ. of Mississippi Medical Center, Jackson
OSTI Identifier:
6151923
Resource Type:
Journal Article
Journal Name:
Am. J. Physiol.; (United States)
Additional Journal Information:
Journal Volume: 251:2
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; AMINO ACIDS; BIOCHEMISTRY; ELECTROLYTES; RENAL CLEARANCE; IODINE 125; KIDNEYS; DYNAMIC FUNCTION STUDIES; ABSORPTION; BLOOD FLOW; DOGS; EXCRETION; FILTRATION; GLOMERULI; IONS; ORGANIC IODINE COMPOUNDS; SODIUM COMPOUNDS; ALKALI METAL COMPOUNDS; ANIMALS; BETA DECAY RADIOISOTOPES; BODY; CARBOXYLIC ACIDS; CHARGED PARTICLES; CHEMISTRY; CLEARANCE; DAYS LIVING RADIOISOTOPES; ELECTRON CAPTURE RADIOISOTOPES; INTERMEDIATE MASS NUCLEI; IODINE ISOTOPES; ISOTOPES; MAMMALS; NUCLEI; ODD-EVEN NUCLEI; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC HALOGEN COMPOUNDS; ORGANS; RADIOISOTOPES; SEPARATION PROCESSES; VERTEBRATES; 551001* - Physiological Systems- Tracer Techniques

Citation Formats

Woods, L L, Mizelle, H L, Montani, J P, and Hall, J E. Mechanisms controlling renal hemodynamics and electrolyte excretion during amino acids. United States: N. p., 1986. Web.
Woods, L L, Mizelle, H L, Montani, J P, & Hall, J E. Mechanisms controlling renal hemodynamics and electrolyte excretion during amino acids. United States.
Woods, L L, Mizelle, H L, Montani, J P, and Hall, J E. 1986. "Mechanisms controlling renal hemodynamics and electrolyte excretion during amino acids". United States.
@article{osti_6151923,
title = {Mechanisms controlling renal hemodynamics and electrolyte excretion during amino acids},
author = {Woods, L L and Mizelle, H L and Montani, J P and Hall, J E},
abstractNote = {Our purpose was to investigate the mechanisms by which increased plasma amino acids elevate renal blood flow (RBF) and glomerular filtration rate (GFR). Since transport of amino acids and Na is linked in the proximal tubule, the authors hypothesized that increased amino acids might stimulate proximal tubular Na reabsorption (PR/sub Na/) and thus increase RBF and GFR by a macula densa feedback mechanism. A solution of four amino acids (Ala, Ser, Gly, Pro) was infused intravenously into anesthetized dogs with normal kidneys (NK) and with kidneys in which the tubuloglomerular feedback mechanism was blunted by lowering renal artery pressure (LPK) or blocked by making the kidneys nonfiltering (NFK). In NK, RBF and GFR increased by 35 +/- 4% and 30 +/- 7% after 90 min of amino acid infusion, while PR/sub Na/ (estimated from lithium clearance) and O2 consumption increased by 31 +/- 5% and 29 +/- 5% and distal Na delivery remained relatively constant. Autoregulation of RBF and GFR in response to step deceases in renal artery pressure was impaired during amino acids in NK. The hemodynamic responses to amino acids were abolished in LPK and NFK. Infusion of the nonmetabolized -aminoisobutyric acid into NK produced changes in renal hemodynamics that were similar to the responses observed with the four metabolizable amino acids. These data are consistent with the hypothesis that elevation of plasma amino acids increases RBF and GFR by a mechanism that requires an intact macula densa feedback. Metabolism of the amino acids does not appear to be necessary for these changes to occur.},
doi = {},
url = {https://www.osti.gov/biblio/6151923}, journal = {Am. J. Physiol.; (United States)},
number = ,
volume = 251:2,
place = {United States},
year = {Fri Aug 01 00:00:00 EDT 1986},
month = {Fri Aug 01 00:00:00 EDT 1986}
}