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ARS Home » Research » Publications at this Location » Publication #101288
Title: METABOLISM IN RATS OF CONJUGATED LINOLEIC ACID RELATIVE TO LINOLEIC ACID

Author
item ADLOF, RICHARD
item BANNI, S - UNIV OF CAGLIARI, ITALY
item IP, C - ROSWELL PARK CANCER INST

Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: 5/10/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Twelve female Sprague-Dawley rats (50 days old) were fed 1 week with 5% olive oil AIN-76A based diet containing 1% Nu-Chek-Prep CLA. After 1 week of unlabeled conjugated linoleic acid (CLA) prefeeding, three rats were sacrificed for baseline data. Remaining nine rats were gavaged each day with 0.5 g of triolein vehicle containing ca. 35 mg each of 9c,11t-18: 2-17,17,18,18-d4 (d-CLA) and 9c,12c-18:2-12,13-d2 (d-Lo). Oral dosing was done in late afternoon. All rats were switched to CLA-free diet after start of d-CLA dosing. Three rats were sacrificed at 2, 4 or 6 days later. Brain, heart, adipose (peritoneal fat), blood (plasma), and liver were isolated and stored at -80 C. Samples were extracted and a portion converted to FAME for total lipid analysis. We followed elimination of non-labelled CLA, incorporation/metabolism of d-CLA and d-Lo, and compared relative rates of CLA and Lo absorption. Rates of fatty acid uptake and clearance varied widely among tissues. After 6 days, CLA composition in heart tissue was reduced 85%, in liver tissue >90%, and in peritoneal fat 33%. CLA composition of brain remained constant, but very low (0.03-0.09% of total lipids); only 0.02-0.03% of d-CLA was incorporated after 6 days. CLA/Lo acyltransferase selectivity varied among tissues. d-Lo was incorporated/metabolized more rapidly than d-CLA tissues except brain (equal uptake, low incorporation), with factors (+/- 20%) of 44X for heart, 10X for liver, 2X for peritoneal fat, and 1.5X for plasma. CLA-d2 (from isomerization of Lo-d2) was detected at 0.1-0.3% in all tissues except in heart (0.02%) and brain (nd). Metabolites of CLA-d4 (18:3w7-d4) were detected in heart (0.01%) and peritoneal fat (0.2%) but not in brain or liver.