scholarly journals Diet fat influences liver plasma-membrane lipid composition and glucagon-stimulated adenylate cyclase activity

1983 ◽  
Vol 212 (3) ◽  
pp. 573-583 ◽  
Author(s):  
P J Neelands ◽  
M T Clandinin

Rats were fed diets that differed in fatty acid composition or in the proportion of energy derived from fat to determine if alteration of dietary fat intake influences the structural lipid composition of liver plasma membrane and the expression of an associated hormone-receptor-mediated function. Weanling rats were fed 9% (w/w) or 20% (w/w) low-erucic acid rape-seed oil or 9% (w/w) soya-bean oil for 24 days. Plasma membranes were isolated and the effect of diet fat on the fatty acid composition of phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol and sphingomyelin was determined. Diet fat significantly altered total saturated and (omega-9) and (omega-6)-unsaturated fatty acid composition in addition to the (omega-6)- to (omega-3)-unsaturated fatty acid ratio in these polar lipids. Feeding the high-fat diet increased the (omega-6)- to (omega-3)-unsaturated fatty acid ratio and the (omega-9)-unsaturated fatty acid content in all lipids except sphingomyelin. Assay of glucagon-stimulated adenylate cyclase activity at both high and low glucagon concentrations indicated that high-fat intake also decreased cyclic AMP formation. In a second experiment the fat intake was held constant (40% of energy) and oleic acid was substituted for linoleic acid by blending high- and low-linoleic acid-type safflower oils. This experiment established that a dose-response relationship exists between dietary intake of fatty acid and the fatty acid composition of plasma-membrane phospholipids. Specific diet-induced transitions in membrane phospholipid fatty acid composition were paralleled by changes in glucagon-stimulated adenylate cyclase activity. This study suggests that transitions in dietary fat intake can alter a hormone-receptor-mediated enzyme function in vivo by changing the surrounding lipid environment.

2013 ◽  
Vol 26 (1) ◽  
pp. 67-74 ◽  
Author(s):  
Mehdi Nikoo ◽  
Mohammad Reza Ghomi

OBJECTIVE: The objective of this study was to investigate the effect of frying oils (canola, hydrogenated sunflower and soybean oils) available commercially and chill storage on the proximate and fatty acid composition of fried slices of farmed great sturgeon (Huso huso). METHODS: Slices of farmed great sturgeon were fried for four minutes at 160ºC in a deep-fryer using different frying oils (canola, hydrogenated sunflower and soybean oils). The oil-to-slice ratio was 2:1. After frying, the slices were allowed to be air cooled for two minutes prior to analysis. For performing the analysis, each of the abovementioned batches was divided into two groups: one group was analysed immediately after frying and the second group was chill-stored at 4ºC for three days and then analysed. RESULTS: After frying, the moisture content decreased while that of fat increased. Fatty acid composition of the slices is affected by type of frying oil. Frying increased the omega-6-to-omega-3 (n-6:n-3) fatty acid ratio while decreased Eicosapentaenoic Acid (C20:5 n-3) and Docosahexaenoic Acid (C22:6 n-3) contents. Proximate and fatty acid composition of raw slices did not change after chill storage. However, in fried- and chill-stored slices, Eicosapentaenoic Acid and Docosahexaenoic Acid contents decreased, while linoleic acid content increased. CONCLUSION: The fatty acid composition of the fried slices tended to resemble that of the frying oils, indicating fatty-acid equilibrium between oils and slices and, during chill storage, it is influenced by the type of frying oil. Slices fried with canola oil had omega-6-to-omega-3 ratios in the ranges recommended for human health.


2014 ◽  
Vol 11 (3) ◽  
pp. 1107-1112
Author(s):  
Baghdad Science Journal

The fatty acid composition in the seed and flower of Ligustrun lucidum and olive oil was studied by Gas Chromatography. Results showed that the main components of seed oil were Palmitic (C16:0) 5,893% ,Palmitolic acid (C16:1)0,398%, Steaeic (C18:0)2,911% ,Oleic (C18:1)74,984%,Linoleic (C18:2) 12,959%,and Linolenic (C18:3) 0,997%. The proportion of unsaturated fatty acid was above 89,338%, so the seed oil of L. lucidum ait belonged to unsaturated oil which possessed promising application. The components of flower oil were Palmitic (C16:0) 65,674% ,Palmitolic acid (C16:1)6,516%, Steaeic (C18:0)2,641% ,Oleic (C18:1)14,707%,Linoleic (C18:2) 3,113%,and Linolenic (C18:3) 2,70%. The proportion of unsaturated fatty acid and saturated fatty acid was above 26,406%, 68,315%,respectively so the flower oil of ligustrun lucidum belonged to saturated oil . the main components of olive oil were Palmitic (C16:0) 13,364% ,Palmitolic acid (C16:1)0,834%, Steaeic (C18:0)3,860% ,Oleic (C18:1) 68,668%,Linoleic (C18:2) 12,586%,and Linolenic (C18:3) 0,687%. The proportion of unsaturated fatty acid was above 82,775%, so the olive oil of ligustrun lucidum ait belonged to. These values of seed oil are very similar to that found in the olive oil.


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