Document Detail

Transport of glutamine across blood-facing membranes of perfused rat jejunum.
MedLine Citation:
PMID:  2650566     Owner:  NLM     Status:  MEDLINE    
Transport of glutamine and other neutral amino acids across the blood-facing membranes of isolated, dually perfused rat jejunum was measured using a paired-tracer isotope-dilution technique. Glutamine, asparagine, histidine, alanine, and leucine showed mutual inhibition of transport. The major component of physiological glutamine transport was saturable (Km = 0.88 +/- 0.15 mM, Vmax = 454 +/- 49 nmol.g-1.min-1; mean +/- SE), stereospecific and Na-independent and appeared to exhibit symmetry of glutamine transport; it most resembled system L. The minor Na-dependent component of glutamine transport resembled system A, i.e., it transported N-methylaminoisobutyric acid (Km approximately equal to 10 microM, Vmax approximately equal to 1.2 nmol.g-1.min-1). At 0.5 mM glutamine transport was insensitive to insulin and glucagon and was unaffected by perfusate pH (7.0-7.8). Glutamine extracted by the jejunum is rapidly utilized; at physiological blood glutamine concentrations the basolateral glutamine-transporter flux may thus not only restrict intestinal glutamine catabolism but also the consequent release of glutamine-derived ammonia (a substrate and stimulant of ureogenesis) into the portal circulation.
P M Taylor; C J Egan; M J Rennie
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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:  256     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1989 Apr 
Date Detail:
Created Date:  1989-05-18     Completed Date:  1989-05-18     Revised Date:  2009-09-29    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  E550-8     Citation Subset:  IM    
Department of Anatomy and Physiology, University of Dundee, United Kingdom.
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MeSH Terms
Amino Acids / metabolism
Aminoisobutyric Acids / metabolism
Biological Transport / drug effects
Blood Flow Velocity
Blood Vessels / metabolism
Cell Membrane / metabolism
Glucagon / pharmacology
Glutamine / blood*,  metabolism
Insulin / pharmacology
Intestinal Mucosa / metabolism
Jejunum / blood supply*,  metabolism
Meglumine / pharmacology
Rats, Inbred Strains
Sodium / pharmacology
Grant Support
//Wellcome Trust
Reg. No./Substance:
0/Amino Acids; 0/Aminoisobutyric Acids; 11061-68-0/Insulin; 2566-34-9/2-(methylamino)isobutyric acid; 56-85-9/Glutamine; 6284-40-8/Meglumine; 7440-23-5/Sodium; 9007-92-5/Glucagon

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

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