Effect of n-3 and n-6 fatty acids on hepatic microsomal lipid metabolism: a time course study.
The present study examines the time dependent effects of n-6 and n-3 polyunsaturated fatty acids on liver microsomal lipid metabolism in FVB mice fed a diet supplemented with a mixture of free fatty acids (mainly 18:3n-6 and 20:5n-3) at 25 mg/g diet. Significant changes in the fatty acid composition of total liver and microsomal lipids were observed after 7 days on the diets. Thereafter, some animals remained on the same diet while others were fed a diet supplemented with hydrogenated coconut oil (HCO). With the exception of 20:5n-3 which showed a slower recovery, establishment of the HCO pattern was rapid indicating that the diet-induced changes could be easily reversed. The unsaturation index, the cholesterol/phospholipid ratio and the microviscosity of the microsomal membranes were not affected by these dietary manipulations. Unsaturated fatty acid supplementation reduced the activity of delta 9 desaturase by 50%. Feeding the HCO diet to mice previously fed the EPA/GLA diet led to a progressive increase in delta 9 desaturase activity, reaching 80% of the day zero values after 14 days. The monoene content of hepatic total lipids reflected, in most cases, the changes in enzyme activity. This study shows that a low dose of a n-3 and n-6 free fatty acid mixture increases the quantities of members of the n-3 family, without loss of n-6 fatty acids in microsomal membranes and modifies the activity of delta 9 desaturase without altering the microsome physicochemical parameters.
de Antueno
R J
RJ
Efamol Research Institute, Kentville, Nova Scotia, Canada.
Cantrill
R C
RC
Huang
Y S
YS
Raha
S K
SK
Elliot
M
M
Horrobin
D F
DF
D000818:Animals; D000074263:Coconut Oil; D004041:Dietary Fats / Q000494:pharmacology*; D044943:Fatty Acid Desaturases / Q000378:metabolism*; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D005260:Female; D050356:Lipid Metabolism; D051379:Mice; D008815:Mice, Inbred Strains; D008862:Microsomes, Liver / Q000187:drug effects* / Q000378:metabolism; D010938:Plant Oils / Q000494:pharmacology; D013995:Time
D004041:Dietary Fats; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D010938:Plant Oils; D044943:Fatty Acid Desaturases; D000074263:Coconut Oil