Document Detail


The cytochemical demonstration of GERL in rat hepatocytes during lipoprotein mobilization.
MedLine Citation:
PMID:  563889     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
When a semisynthetic diet containing 1% orotic acid (OA) is fed to rats, the endoplasmic reticulum (ER) of hepatocytes vesiculates and lipoprotein (LP) droplets accumulate within the vesicles. When clofibrate (ethyl chlorophenoxyisobutyrate, CPIB) is added to the orotic acid-rich diet, the ER cisternae reform and the LP is mobilized through the reconstituted ER. A remarkable restoration of normal hepatocyte ultrastructure occurs except for a few organelles. From their morphological appearance it was suggested that cisternae which became dilated with small LP particles were part of GERL, abnormally enlarged. The present communication validates this interpretation through ultrastructural cytochemistry which can distinguish GERL from the adjacent Colgi apparatus. GERL shows acid phosphatase (AcPase) but not thiamine pyrophosphatase (TPPase) activity. In contrast, the adjacent Golgi element shows thiamine pyrophosphatase but not acid phosphatase activity. From such cytochemical studies we have recently proposed that GERL in normal rat hepatocytes may be involved in transforming LP particles, by enzymes like lipases that were presumed to be present in this hydrolase-rich portion of smooth ER. In the situation studied in this communication, the addition of ethyl chlorophenoxyisobutyrate to the diet causes the release from the ER of large amounts of LP to the Golgi apparatus and to GERL. Apparently the capacity of GERL to metabolize LP is exceeded and lipid accumulates in the residual bodies.
Authors:
P M Novikoff; A Yam
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society     Volume:  26     ISSN:  0022-1554     ISO Abbreviation:  J. Histochem. Cytochem.     Publication Date:  1978 Jan 
Date Detail:
Created Date:  1978-03-29     Completed Date:  1978-03-29     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9815334     Medline TA:  J Histochem Cytochem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1-13     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Acid Phosphatase / analysis
Animals
Endoplasmic Reticulum / enzymology,  metabolism,  ultrastructure*
Golgi Apparatus / enzymology,  ultrastructure
Lipoproteins / metabolism*
Liver / metabolism,  ultrastructure*
Orotic Acid / metabolism
Rats
Thiamine Pyrophosphatase / analysis
Chemical
Reg. No./Substance:
0/Lipoproteins; 65-86-1/Orotic Acid; EC 3.1.3.2/Acid Phosphatase; EC 3.6.1.-/Thiamine Pyrophosphatase

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


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