Document Detail


The questionable role of a microsomal delta8 acyl-coA-dependent desaturase in the biosynthesis of polyunsaturated fatty acids.
MedLine Citation:
PMID:  10984110     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Several experimental approaches were used to determine whether rat liver and testes express an acyl-CoA-dependent delta8 desaturase. When [1-14C]5,11,14-eicosatrienoic acid was injected via the tail vein, or directly into testes, it was incorporated into liver and testes phospholipids, but it was not metabolized to other labeled fatty acids. When [1-14C]11,14-eicosadienoic acid was injected, via the tail vein or directly into testes, or incubated with microsomes from both tissues, it was only metabolized to 5,11,14-eicosatrienoic acid. When ethyl 5,5,11,11,14,14-d6-5,11,14-eicosatrienoate was fed to rats maintained on a diet devoid of fat, it primarily replaced esterified 5,8,11-eicosatrienoic acid, but not arachidonic acid. No labeled linoleate or arachidonate were detected. Dietary ethyl linoleate and ethyl 19,19,20,20-d4-1,2-13C-11,14-eicosadienoate were about equally effective as precursors of esterified arachidonate. The doubly labeled 11,14-eicosadienoate was metabolized primarily by conversion to 17,17,18,18-d4-9,12-ocatdecadienoic acid, followed by its conversion to yield esterified arachidonate, with a mass four units greater than endogenous arachidonate. In addition, the doubly labeled substrate gave rise to a small amount of arachidonate, six mass units greater than endogenous arachidonate. No evidence was obtained, with the radiolabeled substrates, for the presence of a delta8 desaturase. However, the presence of an ion, six mass units greater than endogenous arachidonate when doubly labeled 11,14-eicosadienoate was fed, suggests that a small amount of the substrate may have been metabolized by the sequential use of delta8 and delta5 desaturases.
Authors:
Q Chen; F Q Yin; H Sprecher
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Lipids     Volume:  35     ISSN:  0024-4201     ISO Abbreviation:  Lipids     Publication Date:  2000 Aug 
Date Detail:
Created Date:  2000-12-11     Completed Date:  2001-03-01     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  0060450     Medline TA:  Lipids     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  871-9     Citation Subset:  IM    
Affiliation:
Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus 43210, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Arachidonic Acid / metabolism
Arachidonic Acids / metabolism
Chromatography, Gas
Chromatography, High Pressure Liquid
Diet, Fat-Restricted
Fatty Acid Desaturases / metabolism,  physiology*
Fatty Acids, Unsaturated / biosynthesis*
Ions / chemistry
Linoleic Acids / metabolism
Liver / enzymology
Male
Microsomes / enzymology*
Microsomes, Liver / enzymology,  metabolism
Rats
Testis / enzymology
Time Factors
Grant Support
ID/Acronym/Agency:
DK48744/DK/NIDDK NIH HHS
Chemical
Reg. No./Substance:
0/Arachidonic Acids; 0/Fatty Acids, Unsaturated; 0/Ions; 0/Linoleic Acids; 15541-36-3/eicosa-5,11,14-trienoic acid; 506-32-1/Arachidonic Acid; 544-35-4/ethyl linoleate; EC 1.14.19.-/Fatty Acid Desaturases; EC 1.14.99.-/delta-5 fatty acid desaturase; EC 1.14.99.-/delta-8 fatty acid desaturase

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


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