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ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #69404
Title: CHARACTERIZATION OF PATHWAYS OF ENDOGENOUS SYNTHESIS OF LONG CHAIN POLYUNSATURATED (LC-PUFA) FATTY ACIDS IN PIGLETS

Author
item Heird, William
item SAUERWALD, THORSTEN - BAYLOR COLL OF MEDICINE
item Hachey, David
item WYKES, LINDA - BAYLOR COLL OF MEDICINE

Submitted to: American Pediatric Society / The Society for Pediatric Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/6/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The enrichment pattern of fatty acids (FA) in plasma phospholipids (PL) following administration of (U13C)18:3n-3 suggests that infants utilize an alternative pathway involving C-24 PUFA for endogenous synthesis of C22:6n- 3 (Hachey et al., Pediatr Res, 1995). However, enrichments of FA in plasma PL may not reflect enrichments in tissue lipids. To clarify this issue and, ,hence, strengthen evidence that the alternative pathway is involved, enrichments of the (M+18) isotopomers of FA in plasma and liver PL were determined serially (by negative chemical ionization GC/MS) in piglets given intravenous bolus doses of (U-13C)18:3n-3 and (U-13C)18:2n-6 at 5 days of age. Enrichment patterns of n-3 FA of plasma and liver PL were similar and also similar to the pattern observed in plasma PL of infants, supporting the previous suggestion that infants utilize the alternative pathway for endogenous synthesis of C22:6n-3 (ie, C18:3n-3 C22:5n-3 C24:5n-3 C24:6n-3 C22:6n-3). Enrichment patterns of n-6 fatty acids in plasma and liver PL were consistent with a similar pathway for synthesis of C22:5n-6 (ie, C18:2n-6 C22:4n-6 C24:4n-6 C24:5n-6 C22:5n-6). We conclude that endogenous synthesis of both n-3 and n-6 LC-PUFA involves C24 PUFA and that the apparent synthetic pathway based on the enrichment pattern of plasma FAs reflects the pathway in liver. The alternative pathway described provides a logical explanation of precursor inhibition of LC-PUFA synthesis and is important in understanding effects of 18:3n-3 and 18:2n-6 as well as LC-PUFA intakes on endogenous synthesis of LC-PUFA by human infants.