Metabolism of cholesterol is altered in the liver of C3H mice fed fats enriched with different C-18 fatty acids.
We examined whether the degree of saturation of C-18 fatty acids influenced hepatic cholesterol metabolism in C3H mice. The mice were fed diets containing 20 g/100 g fat, enriched in stearic (18:0), oleic (18:1) or linoleic acid (18:2) with or without 1 g/100 g cholesterol. Plasma total cholesterol concentration was lower in mice fed the 18:0 diet relative to those fed the 18:1- or 18:2-enriched diets (P < 0.05) regardless of dietary cholesterol supplementation. Dietary cholesterol significantly raised hepatic total cholesterol concentration (P < 0.05) in those fed the 18:1- and 18:2-enriched diets, but not in mice fed the 18:0-enriched diet. Dietary cholesterol raised biliary cholesterol concentration (P < 0. 05) in mice fed the 18:1- and 18:2-enriched diets, but not in mice fed the 18:0-enriched diet. The cholesterol saturation index was variably affected by the fat diets. Feeding diets containing cholesterol suppressed the hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) activity and induced acyl coenzyme A:cholesterol acyl transferase (ACAT) activity compared with feeding diets without cholesterol (P < 0.05), indicating that the liver was exposed to dietary cholesterol. Hepatic ACAT activity was lower in mice fed the 18:0-enriched diet compared with those fed the 18:1- or 18:2-enriched diets (P < 0.05). Addition of cholesterol to the 18:1 diet induced the largest increase of hepatic ACAT activity, and this was associated with the enrichment of VLDL with cholesterol. Varying the degree of saturation of C-18 fatty acids influences the metabolism and disposition of hepatic cholesterol.
Cheema
S K
SK
Lipid and Lipoprotein Research Group and Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2S2, Canada.
Agellon
L B
LB
D000818:Animals; D001646:Bile / Q000737:chemistry / Q000378:metabolism; D002784:Cholesterol / Q000097:blood / Q000378:metabolism*; D002790:Cholesterol 7-alpha-Hydroxylase / Q000378:metabolism; D004041:Dietary Fats / Q000494:pharmacology*; D004042:Dietary Fats, Unsaturated / Q000494:pharmacology; D005227:Fatty Acids / Q000032:analysis / Q000494:pharmacology*; D005231:Fatty Acids, Unsaturated / Q000032:analysis / Q000494:pharmacology*; D005260:Female; D006903:Hydroxymethylglutaryl CoA Reductases / Q000378:metabolism; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D051379:Mice; D008809:Mice, Inbred C3H; D008862:Microsomes, Liver / Q000378:metabolism; D002785:Sterol O-Acyltransferase / Q000378:metabolism
D004041:Dietary Fats; D004042:Dietary Fats, Unsaturated; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D002784:Cholesterol; D006903:Hydroxymethylglutaryl CoA Reductases; D002790:Cholesterol 7-alpha-Hydroxylase; D002785:Sterol O-Acyltransferase