Document Detail

Inhibition of L-alanine uptake into bovine jejunal brush border membrane vesicles by L-amino acids.
MedLine Citation:
PMID:  3597936     Owner:  NLM     Status:  MEDLINE    
Jejunal epithelial cells from slaughtered Holstein cows were fractionated to obtain purified brush border membranes from which membrane vesicles were prepared for use in amino acid uptake studies. Uptake of alanine was determined by incubation of vesicles with a solution containing radiolabelled alanine, isolation of vesicles and accumulated alanine by filtration, and detection of accumulated alanine by liquid scintillation counting. Uptake studies were conducted under conditions shown to provide linear rates of accumulation. Sodium-dependent active transport was determined as the difference between uptake measured in the presence and absence of sodium in the extravesicular buffer. Inhibition of alanine uptake increased with increasing extra-vesicular inhibitor concentration until a plateau value was reached. Inhibition of sodium-dependent alanine uptake by 100 mM glycine was 72%; 25 mM isoleucine, valine, or methionine completely inhibited initial alanine uptake. These results indicate the existence of at least two sodium-dependent transport systems, one capable and one incapable of accepting glycine for transport. At concentrations designed to represent expected concentrations of free amino acids in intestinal digesta, several equimolar mixtures (.2 to 5 mM) of 20 amino acids inhibited alanine uptake, suggesting that significant interaction among amino acids for uptake may be occurring under in vivo conditions.
B A Crooker; J H Clark
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of dairy science     Volume:  70     ISSN:  0022-0302     ISO Abbreviation:  J. Dairy Sci.     Publication Date:  1987 May 
Date Detail:
Created Date:  1987-07-31     Completed Date:  1987-07-31     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985126R     Medline TA:  J Dairy Sci     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  963-9     Citation Subset:  IM    
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MeSH Terms
Alanine / metabolism*
Amino Acids / pharmacology*
Biological Transport / drug effects
Cattle / metabolism*
Jejunum / cytology,  drug effects,  metabolism*
Microvilli / drug effects,  metabolism
Reg. No./Substance:
0/Amino Acids; 56-41-7/Alanine

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

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