Document Detail


Processing of calcitonin and epidermal growth factor after binding to receptors in human breast cancer cells (T 47D).
MedLine Citation:
PMID:  6293464     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
125I-labelled calcitonin and 125I-labelled epidermal growth factor (EGF) bound to T 47D breast cancer cells at 37 degrees C in a manner that became increasingly resistant to removal by acid pH. Bound 125I-labelled EGF became resistant to acid removal more rapidly than did bound 125I-labelled calcitonin. The shift from acid accessibility to acid inaccessibility was energy-dependent since it was not seen at 4 degrees C and was inhibited in the presence of cell metabolic inhibitors. Radioactivity removed by acid represented intact hormone as assessed by trichloroacetic acid precipitation, whereas radioactivity released spontaneously by the cells was trichloroacetic acid-soluble. Inclusion of 10 mM-NH4Cl in the incubation medium resulted in an accumulation of cell-associated radioactivity without affecting the shift to acid inaccessibility. The accumulated radioactivity was relatively more trichloroacetic acid-precipitable in comparison with that associated with control cells. These data are consistent with internalization of receptor-bound EGF and a similar though slower mechanism of processing for receptor-bound calcitonin. The predominant route of hormone release from cells seems to occur via intracellular degradation rather than dissociation from cell-surface receptors.
Authors:
D M Findlay; K W Ng; M Niall; T J Martin
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Biochemical journal     Volume:  206     ISSN:  0264-6021     ISO Abbreviation:  Biochem. J.     Publication Date:  1982 Aug 
Date Detail:
Created Date:  1983-01-07     Completed Date:  1983-01-07     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  2984726R     Medline TA:  Biochem J     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  343-50     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Ammonium Chloride / pharmacology
Antimetabolites / pharmacology
Breast Neoplasms / metabolism*,  pathology
Calcitonin / metabolism*
Cells, Cultured
Epidermal Growth Factor / metabolism*
Female
Humans
Hydrogen-Ion Concentration
Receptor, Epidermal Growth Factor
Receptors, Calcitonin
Receptors, Cell Surface / metabolism*
Chemical
Reg. No./Substance:
0/Antimetabolites; 0/Receptors, Calcitonin; 0/Receptors, Cell Surface; 12125-02-9/Ammonium Chloride; 62229-50-9/Epidermal Growth Factor; 9007-12-9/Calcitonin; EC 2.7.10.1/Receptor, Epidermal Growth Factor
Comments/Corrections

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


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