Document Detail


Evidence for predominantly paracellular transport of thyrotropin-releasing hormone across CACO-2 cell monolayers.
MedLine Citation:
PMID:  8267614     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Uptake, transport, and metabolism of tripeptide thyrotropin-releasing hormone were examined in the human intestinal epithelial cell line, Caco-2. A linear relationship between rate and concentration was observed for both the uptake and the transport of thyrotropin-releasing hormone across Caco-2 cell monolayers. Transport of thyrotropin-releasing hormone was not affected by the presence of dipeptide glycylsarcosine, amino acid glycine, tripeptide thyrotropin-releasing hormone free acid as well as active transport inhibitors 2,4-dinitrophenol, sodium azide, ouabain, and amiloride. There was no formation of metabolites during the course of thyrotropin-releasing hormone transport across Caco-2 cells. Incubation of Caco-2 cell homogenate with thyrotropin-releasing hormone, however, showed a time-dependent hydrolysis of thyrotropin-releasing hormone and the formation of thyrotropin-releasing hormone free acid. Increased rate of transport in the presence of EDTA indicates a paracellular passive diffusion as the major route for the transport of TRH. The hydrolytic enzyme present in Caco-2 cells appeared to have little or no access to TRH during the transcellular transport across Caco-2 cell monolayers.
Authors:
L S Gan; T Niederer; C Eads; D Thakker
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Biochemical and biophysical research communications     Volume:  197     ISSN:  0006-291X     ISO Abbreviation:  Biochem. Biophys. Res. Commun.     Publication Date:  1993 Dec 
Date Detail:
Created Date:  1994-01-25     Completed Date:  1994-01-25     Revised Date:  2005-11-17    
Medline Journal Info:
Nlm Unique ID:  0372516     Medline TA:  Biochem Biophys Res Commun     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  771-7     Citation Subset:  IM    
Affiliation:
Department of Drug Metabolism, Glaxo Inc. Research Institute Research Triangle Park, NC 27709.
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MeSH Terms
Descriptor/Qualifier:
2,4-Dinitrophenol
Adenocarcinoma
Amiloride / pharmacology
Azides / pharmacology
Biological Transport / drug effects
Cell Line
Cell Membrane / drug effects,  metabolism
Colonic Neoplasms
Dinitrophenols / pharmacology
Dipeptides / pharmacology
Edetic Acid / pharmacology
Epithelium / metabolism
Glycine / pharmacology
Humans
Intestines
Kinetics
Ouabain / pharmacology
Sodium Azide
Thyrotropin-Releasing Hormone / metabolism*
Tritium
Tumor Cells, Cultured
Chemical
Reg. No./Substance:
0/Azides; 0/Dinitrophenols; 0/Dipeptides; 10028-17-8/Tritium; 24305-27-9/Thyrotropin-Releasing Hormone; 2609-46-3/Amiloride; 26628-22-8/Sodium Azide; 29816-01-1/glycylsarcosine; 51-28-5/2,4-Dinitrophenol; 56-40-6/Glycine; 60-00-4/Edetic Acid; 630-60-4/Ouabain

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


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