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Elongation predominates over desaturation in the metabolism of 18∶3n−3 and 20∶5n−3 in turbot ( Scophthalmus maximus ) brain astroglial cells in primary culture
Author(s) -
Tocher Dauglas R.
Publication year - 1993
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/bf02536309
Subject(s) - turbot , polyunsaturated fatty acid , docosahexaenoic acid , arachidonic acid , metabolism , biochemistry , linoleic acid , eicosapentaenoic acid , biology , phosphatidylinositol , fatty acid , fatty acid desaturase , enzyme , signal transduction , fish <actinopterygii> , fishery
The origin of docosahexaenoic acid (DHA, 22∶6n−3) that accumulates in turbot brain during development was investigated by studying the incorporation and metabolism via the desaturase/elongase pathways of [1‐ 14 C]‐labelled polyunsaturated fatty acids (PUFA) in primary cultures of brain astrocytic glial cells. There was little specificity evident in the total incorporation of PUFAs into the turbot astrocytes. However, specificity was apparent in the distribution of the various PUFAs among the individual lipid classes. In particular, there was very specific incorporation of [ 14 C]arachidonic acid (AA, 20∶4n−6) into phosphatidylinositol balanced by a lower incorporation of this acid into total diradyl glycerophosphocholines. [ 14 C]‐Linolenic acid (LNA, 18∶3n−3) and [ 14 C]eicosapentaenoic acid (EPA, 20∶5n−3) were metabolized via the desaturase/elongase pathways to a significantly greater extent than [ 14 C]linoleic acid (18∶2n−6) and [ 14 C]AA. The turbot astrocytes expressed very little Δ5 desaturase activity and only low levels of Δ4 desaturation activity. Although the percentages were small, approximately 4–5 times as much labelled DHA was produced from [ 14 C]EPA compared with [ 14 C]LNA. However, it was concluded that very little DHA in the turbot brain could result from the metabolism of LNA and EPA in astrocytic glial cells.