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Vaccenic acid metabolism in the liver of rat and bovine
Author(s) -
Gruffat Dominique,
De La Torre Anne,
Chardigny JeanMichel,
Durand Denys,
Loreau Olivier,
Bauchart Dominique
Publication year - 2005
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-005-1385-1
Subject(s) - metabolism , clinical chemistry , vaccenic acid , endogeny , biochemistry , in vitro , biology , medicine , chemistry , endocrinology , fatty acid , conjugated linoleic acid , linoleic acid
Hepatic metabolism of vaccenic acid (VA), especially its conversion into CLA, was studied in the bovine (ruminant species that synthesizes CLA) and in the rat (model for nonruminant) by using the in vitro technique of liver explants. Liver tissue samples were collected from fed animals (5 male Wistar rats and 5 Charolais steers) and incubated at 37°C for 17 h under an atmosphere of 95% O 2 /5% CO 2 in medium supplemented with 0.75 mM of FA mixture and with 55 μM [1‐ 14 C]VA. VA uptake was about sixfold lower in bovine than in rat liver slices ( P <0.01). For both species, VA that was oxidized to partial oxidation products represented about 20% of VA incorporated by cells. The chemical structure of VA was not modified in bovine liver cells, whereas in rat liver cells, 3.2% of VA was converted into 16∶0 and only 0.33% into CLA. The extent of esterification of VA was similar for both animal species (70–80% of incorporated VA). Secretion of VA as part of VLDL particles was very low and similar in rat and bovine liver (around 0.07% of incorporated VA). In conclusion, characteristics of the hepatic metabolism of VA were similar for rat and bovine animals, the liver not being involved in tissue VA conversion into CLA in spite of its high capacity for FA desaturation especially in the rat. This indicates that endogenous synthesis of CLA should take place exclusively in peripheral tissues.