DETECTION OF CONJUGATED DIENE ISOMERS OF LINOLEIC-ACID IN LIVER LIPIDS OF RATS FED A CHOLINE-DEVOID DIET INDICATES THAT THE DIET DOES NOT CAUSE LIPOPEROXIDATION

Male and female F-344 rats were fed for 1 week choline-devoid or control choline-supplemented diets containing either 5% corn oil and 10% partially hydrogenated vegetable oils (PHO diets) or 15% corn oil (CO diets). HPLC/second derivative UV spectrophotometric analyses, combined with on-line atmospheric pressure ionization mass spectrometry, were used to determine whether conjugated diene isomers of linoleic acid (CLA), present in the diets, were assimilated into liver and adipose tissue lipids. The CLA content in the PHO diets was an order of magnitude greater than that in the CO diets. CLA were detected in the adipose tissue of all rats but in the liver of only rats fed the PHO diets. In adipose tissue, the CLA levels clearly reflected those present in the diets, and no sex differences, or differences between rats fed the choline-devoid or control diets were noted. In addition to CLA, conjugated linolenic and eicosatrienoic acids, arising probably from desaturation and elongation of CLA, were detected in the liver. The results provide evidence that the conjugated dienes detected in liver lipids of rats fed a PHO-containing choline-devoid diet are of dietary origin and do nor reflect lipid peroxidation.