Document Detail


Differential processing of the two subunits of human choriogonadotropin (hCG) by granulosa cells. I. Preparation and characterization of selectively labeled hCG.
MedLine Citation:
PMID:  6273118     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The alpha- and beta-subunits of hCG were radioiodinated and recombined with unlabeled complementary subunits. The resultant recombined hormones, selectively labeled in either the alpha- or beta-subunit, were separated from unrecombined subunit by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, extracted with Triton X-100, and characterized by binding analysis. The estimates of maximum binding (active fraction) of the two resultant selectively labeled, recombined hCG preparations, determined with excess receptor were 0.41 and 0.59. These values are similar to those obtained when hCG is labeled as an intact molecule. The specific activities of the recombined preparations were estimated by four different methods, and the resulting values were used in combination with the active fraction estimates to determine the concentrations of active free and bound hormone. Binding analyses were run using varying concentrations of both labeled and unlabeled hormone. Estimates of the equilibrium dissociation binding constant (Kd) and receptor capacity were calculated in three different ways. The mean estimates of capacity (52.6 and 52.7 fmol/mg tissue) and Kd (66.6 and 65.7 pM) for the two preparations were indistinguishable. Additionally, these values were similar to values reported previously for hCG radioiodinated as an intact molecule. The availability of well characterized, selectively labeled hCG preparations provides new tools for studying the mechanism of action and the target cell processing of the subunits of this hormone.
Authors:
T D Landefeld; M D Byrne; K L Campbell; A R Midgley
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Endocrinology     Volume:  109     ISSN:  0013-7227     ISO Abbreviation:  Endocrinology     Publication Date:  1981 Dec 
Date Detail:
Created Date:  1982-02-22     Completed Date:  1982-02-22     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0375040     Medline TA:  Endocrinology     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1851-7     Citation Subset:  AIM; IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Binding, Competitive
Chorionic Gonadotropin / metabolism*
Female
Granulosa Cells / metabolism*
Iodine Radioisotopes
Kinetics
Macromolecular Substances
Radioisotope Dilution Technique
Rats
Receptors, Cell Surface / metabolism*
Receptors, LH
Grant Support
ID/Acronym/Agency:
HD-05558/HD/NICHD NIH HHS; HD-1131/HD/NICHD NIH HHS
Chemical
Reg. No./Substance:
0/Chorionic Gonadotropin; 0/Iodine Radioisotopes; 0/Macromolecular Substances; 0/Receptors, Cell Surface; 0/Receptors, LH

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


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