AJP - Regulatory, Integrative and Comparative Physiology, Vol 267, Issue 5 1273-R1279, Copyright © 1994 by American Physiological Society
Preferential incorporation of sn-2 lysoPC DHA over unesterified DHA in the young rat brain
F. Thies, C. Pillon, P. Moliere, M. Lagarde and J. Lecerf
Institut National de la Sante et de la Recherche Medicale U 352, Institut National des Sciences Appliquees-Lyon, Villeurbanne, France.
The uptake and metabolism of [3H]docosahexaenoic acid (DHA) esterified at
the sn-2 position of lysophosphatidylcholine (lysoPC DHA) and in the
unesterified form, both bound to albumin, was studied in 20-day-old rats.
LysoPC DHA was preferentially recovered in the brain (4-5% of the injected
radioactivity) over the unesterified form of DHA (0.3-0.4%). Conversely,
the lysoPC form was taken up less than or at the same extent as the
unesterified form by the liver, heart, and kidney. In the brain, DHA was
mainly recovered in phosphatidylethanolamine whether the esterified or the
unesterified form was used, although DHA from lysoPC was esterified at the
same extent in phosphatidylcholine and phosphatidylethanolamine after 2.5
min. The uptake of labeled palmitic, oleic, linoleic, and arachidonic
acids, esterified or not in lysophosphatidylcholine, was also studied in
brain, liver, heart, and kidney. Only the brain preferentially incorporated
unsaturated (but not saturated) lysoPC, with the uptake increasing with the
degree of unsaturation of the fatty acid moiety. These results strongly
suggest that the young rat brain specifically utilizes
albumin-lysoPC-containing polyunsaturated fatty acids.
