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Eicosapentaenoic and arachidonic acid: Comparison of metabolism and activity in murine epidermal cells
Author(s) -
Belury Martha A.,
Patrick Kelly E.,
Locniskar Mary,
Fischer Susan M.
Publication year - 1989
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/bf02535150
Subject(s) - arachidonic acid , eicosapentaenoic acid , ornithine decarboxylase , metabolism , biochemistry , dna synthesis , prostaglandin , fatty acid , cell culture , biology , 12 o tetradecanoylphorbol 13 acetate , chemistry , microbiology and biotechnology , polyunsaturated fatty acid , enzyme , protein kinase c , in vitro , genetics , phorbol ester
The biological activity, including metabolism and modulation of ornithine decarboxylase activity and DNA synthesis, of arachidonic acid (AA) and eicosapentaenoic acid (EPA) were compared in epidermal cells from SENCAR mice. Radiolabelled AA and EPA were found to be similarly incorporated into and released from membrane phospholipids of unstimulated cultures. However, when cells were stimulated with the tumor promoter 12‐0‐tetradecanoylphorbol‐13‐acetate (TPA), the release of AA was significantly higher than the release of EPA. The extent of metabolism of AA and EPA to prostaglandins was determined in both freeze‐thawed cell preparations and in viable cultured cells. In the freeze‐thawed preparations, use of AA as a substrate resulted in significantly more PGF than when EPA was used as the substrate. However, more PGE 3 was formed than PGE 2 . PGD levels were the same for either fatty acid precursor. Prostaglandin production was also determined in viable cultured cells since other influences such as phospholipase A 2 activity can modify prostaglandin production. Control cultures prelabelled with either AA or EPA produced similar amounts of the respective PGF, PGE, and PGD. However, TPA‐stimulated cultures produced significantly higher amounts of each prostaglandin in cultures prelabelled with AA compared to cells prelabelled with EPA. HETE or HEPE production was the same both for cultured cells prelabelled with AA or EPA and for homogenates from uncultured cells incubated directly with the radiolabelled fatty acids. TPA‐induced ornithine decarboxylase (ODC) was significantly higher in AA‐treated cultures compared to EPA‐treated cultures. AA supports DNA synthesis to a greater extent than EPA, either alone or in the presence of TPA. These findings suggest that AA and EPA do not have equivalent biological activity in mouse epidermal cells.