effects of dietary cholesterol on blood and liver polyunsaturated fatty acids and on plasma cholesterol in rats fed various types of fatty acid diet

• Published in: Lipids Vol. 19; no. 9; pp. 664 - 672
• Main Authors: Huang, Y.S, Manku, M.S, Horrobin, D.F
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer‐Verlag 01.09.1984; Springer
• Subjects: Animals; Biological and medical sciences; Cholesterol - blood; Cholesterol, Dietary - pharmacology; diet-related diseases; Dietary Fats - metabolism; Fatty Acids - blood; Fatty Acids, Nonesterified - blood; Fatty Acids, Nonesterified - metabolism; Fundamental and applied biological sciences. Psychology; human nutrition; Lipids. Glycolipids; Liver - drug effects; Liver - metabolism; Male; Metabolisms and neurohumoral controls; Phospholipids - blood; Rats; Rats, Inbred Strains; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Vertebrata; Mammalia; Rat; Rodentia; Lipids; Metabolism; Fatty acids; Cholesterol; Feeding
• ISSN: 0024-4201; 1558-9307
• DOI: 10.1007/BF02534526

Male rats were fed on a fat‐free diet for 8 weeks and then switched to diets containing 10% hydrogenated coconut oil (HCO), safflower oil (SFO) or evening primrose oil (EPO). Half of each group was also given 1% of cholesterol in the diet. After 5 further weeks, plama, red cell and liver fatty acids were measured in the various lipid fractions. Plasma and liver cholesterol also were estimated. In almost all fractions and on all three diets, feeding cholesterol led to accumulation of the substrates of desaturation reactions and to deficits of the products of these reactions. The results were consistent with inhibition of Δ‐6, Δ‐5 and Δ‐4 desaturation of n−6 essential fatty acids. Since the diets were deficient in n−3 fatty acids, levels were very low but were also consistent with inhibition of desaturation. In contrast, cholesterol had relatively less consistent effects on 20∶3n−9, suggesting that desaturation of n−9 fatty acids was less inhibited. Plasma cholesterol levels rose sharply in the HCO and SFO groups but not at all in the EPO group. EPO contains the product of Δ‐6 desaturation, 18∶3n−6, suggesting that conversion of linoleic acid to 18∶3n−6 and possibly to further metabolites may be important for the cholesterol‐lowering effect of polyunsaturates.