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Dietary n‐6 PUFA deprivation in adult rats increases docosahexaenoic acid metabolism and consumption by brain
Author(s) -
Igarashi Miki,
Kim HyungWook,
Chang Lisa,
Ma Kaizong,
Bell Jane M,
Rapoport Stanley I
Publication year - 2009
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.23.1_supplement.lb417
Subject(s) - docosahexaenoic acid , weaning , medicine , polyunsaturated fatty acid , metabolism , endocrinology , chemistry , biology , fatty acid , biochemistry
We reported that dietary n‐6 PUFA deprivation in post‐weaning rats increases DHA (22:6n‐3) concentration in the brain, whereas decreasing the concentration of AA (20:4n‐6). We hypothesized that the DHA increase would be accompanied by altered kinetics of brain DHA. In this study, we quantified incorporation and turnover rates of DHA into brain phospholipids of unanesthetized male rats fed an n‐6 PUFA adequate diet (27.6% LA, 4.5% ALA) or deficient diet (2.3% LA, 4.8% ANA) for 15 weeks. Rats were infused intravenously with [1‐14C]DHA, arterial plasma was collected, and the brain was microwaved at 5 min and analyzed. n‐6 PUFA deprivation did not change the concentration of any stable brain lipid. Rats fed the deficient compared with adequate diet had less brain AA in brain phospholipids (‐28%~‐11%) and increased DHA in only EtnGpl. DHA incorporation rates from plasma were significantly increased 1.4‐1.8 fold in brain phospholipids, and DHA turnover rates were increased in ChoGpl, PtdIns, and PtdSer. Thus, n‐6 PUFA deprivation increased DHA incorporation and turnover in rat brain. The higher incorporation rates indicate that brain DHA was being lost by metabolism at an accelerated rate, since the incorporation rate of DHA is stochiometrically equal to its rate of metabolic loss from brain. This may indirectly increase dietary demand for DHA.