Physiological effects of an oil rich in γlinolenic acid on hepatic fatty acid oxidation and serum lipid levels in genetically hyperlipidemic mice

Abstract

We investigated the physiological activity of an oil rich in γlinolenic acid of evening primrose origin (containing 42.6% γlinolenic acid) affecting hepatic fatty acid metabolism, and serum lipid levels in genetically hyperlipidemic mice deficient in apolipoprotein E expression. Male apolipoprotein Edeficient mice (BALB/c.KOR/ StmSlcApoeshl) were fed experimental diets containing 100 g/kg of palm oil (saturated fat), safflower oil (rich in linoleic acid), γ linolenic acid oil (rich in γlinolenic acid), or fat mixtures composed of safflower and γlinolenic acid oils (65:35 and 30:70, w/w) for 20 days. γLinolenic acid oil, compared with palm and safflower oils, strongly and dosedependently increased the activity and mRNA levels of hepatic fatty acid oxidation enzymes. In general, safflower and γlinolenic acid oils, compared with palm oil, reduced the activity and mRNA levels of lipogenic enzymes. However, these oils were equivalent in reducing the parameters of lipogenesis, excluding malic enzyme and pyruvate kinase. The diets containing safflower and γlinolenic acid oils, compared with the palm oil diet, significantly decreased serum triacylglycerol and cholesterol levels. The decreases were greater with γlinolenic acid oil than with safflower oil. γLinolenic acid oil exerted strong serum lipidlowering effects in apolipoprotein Edeficient mice apparently through the changes in hepatic fatty acid metabolism.