Document Detail


Intermediates in endogenous synthesis of C22:6 omega 3 and C20:4 omega 6 by term and preterm infants.
MedLine Citation:
PMID:  9029636     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
An alternative pathway of omega 3 and omega 6 fatty acid metabolism has been described in isolated rate hepatocytes and human fibroblasts. This alternative pathway, which is independent of delta 4 desaturation, involves elongation of C22 5 omega 3 and C22:4 omega 6 to C24 fatty acids, delta 6 desaturation of the C24 fatty acids and subsequent beta oxidation of the desaturated products to C22:6 omega 3 and C22:5 omega 6. To determine whether this alternative pathway is operative in the human infant and also to obtain additional information concerning endogenous conversion of C18:3 omega 3 and C18:2 omega 6 to longer chain more unsaturated fatty acids, presence of [M + 18] isotopomers of omega 3 and omega 6 fatty acids in the plasma phospholipid fraction of term and preterm infants after administration of [U-13C]18:3 omega 3 and [U-13C]18:2 omega 6 was determined by negative chemical ionization gas chromatography/mass spectrometry. [M + 18] isotopomers of the following omega 3 fatty acids were detected: C18:3, C18:4, C20:3, C20:4, C20:5, C22:4, C22:5, C22:6, C24:4 (two infants only), C24:5, and C24:6. [M + 18] isotopomers of omega 6 fatty acids detected included only C18:2, C18:3, C20:2, C20:3, and C20:4, but sensitivity was insufficient to detect [M + 18] isotopomers of C22 and C24 omega 6 fatty acids. Presence of [M + 18] isotopomers of C24:5 omega 3 and C24:6 omega 3 indicates that these fatty acids were synthesized endogenously from C18:3 omega 3. This plus the in vitro data strongly suggests that infants use the recently described alternative pathway in endogenous synthesis of C22:6 omega 3. However, involvement also of delta 4 desaturation cannot be excluded. Detection of [M + 18] isotopomers of C20:3 omega 3, C20:2 omega 6, and C22:4 omega 3 suggests that C18:3 omega 3, C18:2 omega 6, and C20:4 omega 3 are elongated as well as desaturated. The specific fate of these elongation products and their importance in endogenous synthesis of omega 3 and omega 6 long chain polyunsaturated fatty acids remain to be determined.
Authors:
T U Sauerwald; D L Hachey; C L Jensen; H Chen; R E Anderson; W C Heird
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Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Pediatric research     Volume:  41     ISSN:  0031-3998     ISO Abbreviation:  Pediatr. Res.     Publication Date:  1997 Feb 
Date Detail:
Created Date:  1997-05-08     Completed Date:  1997-05-08     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0100714     Medline TA:  Pediatr Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  183-7     Citation Subset:  IM    
Affiliation:
USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Houston, Texas 77030, USA.
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MeSH Terms
Descriptor/Qualifier:
Arachidonic Acid / biosynthesis*
Docosahexaenoic Acids / metabolism*
Fatty Acids / metabolism
Gestational Age
Humans
Infant, Newborn / metabolism*
Infant, Premature / metabolism*
Phospholipids / blood
Grant Support
ID/Acronym/Agency:
EY00871/EY/NEI NIH HHS; EY04149/EY/NEI NIH HHS
Chemical
Reg. No./Substance:
0/Fatty Acids; 0/Phospholipids; 25167-62-8/Docosahexaenoic Acids; 506-32-1/Arachidonic Acid

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


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