| Differences in uptake of high-density lipoproteins by rat adrenals using in vivo vs. in situ perfusion techniques. | |
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MedLine Citation:
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PMID: 2742875 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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This study describes the effect of the delivery route of high-density lipoproteins (HDL) on the ultimate fate of the lipoprotein in the intact rat adrenal. Equal amounts of human (h)-derived affinity-purified apoE-free 125I-labeled HDL3 was given to ethinyl estradiol-treated (i.e., lipoprotein-deficient) rats either intravenously (in vivo route) or by non-recycling perfusion (in situ perfusion route). After 60-90 min, the adrenals were either excised and assessed for uptake of radioactivity, or perfusion-fixed with glutaraldehyde and prepared for autoradiograms at the electron microscope level. The results show that hHDL3 circulated in vivo binds 9-times more readily to adrenal tissues than the same quantity of ligand delivered by perfusion. Also, when the lipoprotein is administered in vivo, it is 5-times more likely to be interiorized as an intact particle by zona fasciculata (corticosterone-secreting) cells via an endocytic pathway than when delivered by perfusion. Similar differences between the in vivo and in situ routes were not seen when 125I-labeled rat HDL was the ligand delivered. Whereas the starting hHDL3 ligand was free of apoE, there was a substantial (7-fold) conversion of the HDL3 to apoE-containing HDL3 following in vivo circulation of the ligand, as shown by sodium phosphotungstate-MgCl2 precipitation or heparin-Sepharose column chromatography. These results show that the route of lipoprotein delivery to specific tissues can play a major role in determining both the binding and the processing of the ligand by the tissue in question. With hHDL3, acquisition of apoE during only 1 h of recirculation in lipoprotein-deficient rats was sufficient to totally alter the fate of the ligand in the adrenal cortex. |
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Authors:
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S Azhar; E Reaven |
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Publication Detail:
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Type: Comparative Study; Journal Article |
Journal Detail:
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Title: Biochimica et biophysica acta Volume: 1004 ISSN: 0006-3002 ISO Abbreviation: Biochim. Biophys. Acta Publication Date: 1989 Jul |
Date Detail:
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Created Date: 1989-08-25 Completed Date: 1989-08-25 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0217513 Medline TA: Biochim Biophys Acta Country: NETHERLANDS |
Other Details:
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Languages: eng Pagination: 61-6 Citation Subset: IM |
Affiliation:
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Department of Medicine, Stanford University School of Medicine, Palo Alto, CA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adrenal Cortex
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drug effects,
metabolism* Animals Apolipoproteins E / metabolism Ethinyl Estradiol / pharmacology Lipoproteins, HDL / blood, metabolism* Male Perfusion Rats Rats, Inbred Strains |
| Chemical | |
Reg. No./Substance:
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0/Apolipoproteins E; 0/Lipoproteins, HDL; 57-63-6/Ethinyl Estradiol |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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