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Effect of dietary docosahexaenoic acid on the in vivo net biosynthesis of docosahexaenoic acid from α‐linolenic acid, in rat tissues
Author(s) -
DeMar James Charles,
Martino Carmine,
Lefkowitz William,
Salem Norman
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a239-d
Subject(s) - docosahexaenoic acid , polyunsaturated fatty acid , alpha linolenic acid , in vivo , biochemistry , medicine , endocrinology , chemistry , biology , metabolism , food science , fatty acid , microbiology and biotechnology
Docosahexaenoic acid (DHA; 22:6n‐3) is a long chain n‐3 polyunsaturated fatty acid (n‐3 PUFA) which supports nervous system function. DHA is obtained directly within the diet or synthesized in vivo from α‐linolenic acid (LNA; 18:3n‐3), another more common dietary n‐3 PUFA. Using eight day‐old rat pups as in vivo model, we addressed whether the synthesis of DHA is regulated by the dietary availability of DHA. One group of rats was continuously fed deuterium‐labeled LNA (d5‐LNA) as the only source of n‐3 PUFA (d5‐LNA diet). Another group was fed both d5‐LNA and unlabeled DHA (d5‐LNA + DHA diet). After 20 days of feeding, the rats were killed and the amount of d5‐DHA (synthesized DHA) present in various tissues comprising the whole body was directly quantified by gas chromatographic methods. In the d5‐LNA + DHA group, the presence of dietary DHA markedly decreased (3 – 4 fold) the amount of d5‐DHA that accumulated in the brain, heart, kidney, liver, lung, plasma, retina, skeletal muscle, skin, spleen, and testes. Surprisingly, there was no dietary effect on the amount of d5‐DHA found in brown and white adipose tissues. We have shown here that DHA biosynthesis and accretion is very responsive to the dietary availability of preformed DHA. Our data will be used to construct a model of whole body n‐3 PUFA metabolism, and how it is regulated by input of dietary DHA.