title: Regulation of rat brain polyunsaturated fatty acid (PUFA) metabolism during graded dietary n-3 PUFA deprivation.
abstract: Knowing threshold changes in brain lipids and lipid enzymes during dietary n-3 polyunsaturated fatty acid deprivation may elucidate dietary regulation of brain lipid metabolism. To determine thresholds, rats were fed for 15 weeks DHA-free diets having graded reductions of α-linolenic acid (α-LNA). Compared with control diet (4.6% α-LNA), plasma DHA fell significantly at 1.7% dietary α-LNA while brain DHA remained unchanged down to 0.8% α-LNA, when plasma and brain docosapentaenoic acid (DPAn-6) were increased and DHA-selective iPLA(2) and COX-1 activities were downregulated. Brain AA was unchanged by deprivation, but AA selective-cPLA(2), sPLA(2) and COX-2 activities were increased at or below 0.8% dietary α-LNA, possibly in response to elevated brain DPAn-6. In summary, homeostatic mechanisms appear to maintain a control brain DHA concentration down to 0.8% dietary DHA despite reduced plasma DHA, when DPAn-6 replaces DHA. At extreme deprivation, decreased brain iPLA(2) and COX-1 activities may reduce brain DHA loss.
authors: Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bldg. 9, Room 1S126, Bethesda, MD 20892, USA. peterkhw@gmail.com
authors: Hyung-Wook
authors: HW
authors: Kim
authors: Jagadeesh S
authors: JS
authors: Rao
authors: Stanley I
authors: SI
authors: Rapoport
authors: Miki
authors: M
authors: Igarashi
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology / Q000378:metabolism*; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics / Q000378:metabolism; D051545:Cyclooxygenase 1 / Q000235:genetics / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D004041:Dietary Fats / Q000378:metabolism*; D004281:Docosahexaenoic Acids / Q000172:deficiency*; D005231:Fatty Acids, Unsaturated / Q000097:blood / Q000378:metabolism*; D005260:Female; D015870:Gene Expression; D008084:Lipoxygenase / Q000235:genetics / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D054467:Phospholipases A2 / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D015430:Weight Gain; D017962:alpha-Linolenic Acid / Q000172:deficiency*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D004041:Dietary Fats; D005231:Fatty Acids, Unsaturated; D008565:Membrane Proteins; D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids; D008084:Lipoxygenase; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496513:Ptgs1 protein, rat; C489691:Ptgs2 protein, rat; D054467:Phospholipases A2