Phosphatidylethanolamine methyltransferase: evidence for influence of diet fat on selectivity of substrate for methylation in rat brain synaptic plasma membranes

Hargreaves, K.M.; Clandinin, Michael T.

doi:10.1016/0005-2760(87)90183-4

Cited by 81 publications

(21 citation statements)

References 29 publications

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“…The VLDL portion was extracted by non-equilibrium density-gradient ultracentrifugation [19]. TGs were removed [6] using a Folch extraction, followed by addition of internal standard (17:0), separation by TLC and quantitative recovery of the TG fraction [20]. Following methylation, fatty acid methyl esters (FAMEs) were identified and quantified by GC.…”

Section: Methodsmentioning

confidence: 99%

Synthesis of specific fatty acids contributes to VLDL-triacylglycerol composition in humans with and without type 2 diabetes

et al. 2009

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Aims/hypothesis It is recommended that patients with diabetes reduce their intake of saturated fat and increase their intake of monounsaturated fat or carbohydrate. However, high-carbohydrate diets may result in higher saturated fatty acids in VLDL-triacylglycerol. This is attributed to de novo lipogenesis, although synthesis of specific fatty acids is rarely measured. The objective of this study was to examine the contribution of de novo fatty acid synthesis to VLDL-triacylglycerol composition. It was hypothesised that levels of total and de novo synthesised fatty acids would increase with increased carbohydrate intake in diabetic participants. Methods Seven individuals with type 2 diabetes mellitus and seven matched non-diabetic controls consumed two diets differing in fat energy (lower fat <25%, higher fat >35%) for 3 days in a randomised crossover design. Blood samples were drawn before and 24 h after the ingestion of 2 H-labelled water. ResultsIn the control participants, the higher-fat diet resulted in a 40% reduction in VLDL-triacylglycerol fatty acids because of decreases in myristic, palmitic, palmitoleic and linoleic acids, but the opposite trend occurred in participants with diabetes. The lower-fat diet increased the fractional synthesis rate by 35% and 25% in the control and diabetes participants, respectively (range: 0-33%). Palmitate accounted for 71% of fatty acids synthesised (range: 44-84% total de novo synthesised fatty acids). Conclusions/interpretation 2 H incorporation was used for the first time in humans showing variability in the synthesis rate of specific fatty acids, even palmitic acid. A lower-fat diet stimulated saturated fatty acid synthesis at high rates, but no net stimulation of synthesis of any fatty acid occurred in the diabetes group. The implications of this finding for our understanding of lipid metabolism in diabetes require further investigation.

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Section: Methodsmentioning

confidence: 99%

Synthesis of specific fatty acids contributes to VLDL-triacylglycerol composition in humans with and without type 2 diabetes

et al. 2009

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“…Fatty acid methyl esters were prepared and separated by automated gas-liquid chromatography (GLC) (Varian Instruments, Georgetown, Ontario, Canada) as previously described [32]. These conditions are capable of separating methyl esters of saturated, cis-monounsaturated and cispolyunsaturated fatty acids from 14 to 24 carbon chains in length.…”

Section: Methodsmentioning

confidence: 99%

Effect of w3 fatty acid on plasma lipids, cholesterol and lipoprotein fatty acid content in NIDDM patients

et al. 1997

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Results from animal studies indicate that the type of dietary fat consumed has a profound effect on insulin action in tissues. Feeding a semipurified diet high in polyunsaturated to saturated fatty acid (P/S) ratio to insulin-dependent diabetic rats as compared to feeding them a diet low in P/S ratio increased insulin binding and insulin action in adipocytes [1] and skeletal muscle [2,3]. Alteration in the fatty acid composition of plasma membrane phospholipid by dietary P/S ratio has been suggested to be a cause of these changes in insulin action. Beneficial effects of fish oil in preventing the development of insulin resistance in rats caused by a high intake of saturated fatty acids have also been reported [4,5].Individuals with insulin-dependent diabetes mellitus are prone to develop disorders in lipid and lipoprotein metabolism, of which hyperlipidaemia is the most common [6,7]. Elevated plasma triacylglycerol and reduced HDL cholesterol also increase the risk Diabetologia (1997) Summary This study was conducted to examine the effect of w 3 fatty acid supplementation on plasma lipid, cholesterol and lipoprotein fatty acid content of non-insulin-dependent diabetic individuals consuming a higher (0.65, n = 10) or lower (0.44, n = 18) ratio of dietary polyunsaturated to saturated fatty acid (P/ S). The participants were initially given an olive oil supplement (placebo) equivalent to 35 mg of 18:1 ⋅ kg body weight -1 ⋅ day -1 for 3 months. This was followed by two w 3 supplement periods in a randomized crossover. In these 3-month periods, participants were given a linseed oil supplement equivalent to 35 mg of 18:3w3 ⋅ kg body weight -1 ⋅ day -1 or a fish oil supplement equivalent to 35 mg of 20:5w3 + 22:6w3 ⋅ kg body weight -1 ⋅ day -1 . At the end of each supplement period, a blood sample was drawn from each participant for lipid, lipoprotein, insulin, glucagon and C-peptide analyses. At the end of each 3-month period a 7-day dietary record was completed to calculate dietary fat intake and P/S ratio.Results indicate that fish oil significantly reduced plasma triacylglycerol level (p < 0.05) and increased 20:5w3 and 22:6w3 content of all lipoprotein lipid classes. Linolenic acid supplementation had no effect on plasma triacylglycerol level, but it increased 18:3w3 content of lipoprotein cholesterol ester fractions (p < 0.05). A slight increase in 20:5w3, but not 22:6w3, content was noted in lipoprotein lipid classes as a result of 18:3w3 supplementation. LDL and HDL cholesterol, insulin, glucagon and C-peptide levels were not affected by either w 3 supplement. It is concluded that a modest intake of w 3 fatty acids, such as could be obtained from consuming fish regularly, will reduce plasma triglyceride level without affecting LDL or HDL cholesterol levels. [Diabetologia (1997) Corresponding author: Dr. M. T. Clandinin, Nutrition and Metabolism Research Group, Department of Agriculture, Food and Nutritional Science, University of Alberta, 4-10 Agriculture/Forestry Centre, Edmonton, Alberta T6G 2P5, Canada A...

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“…In addition, a number of functional alterations occur, such as changes in enzymatic activities (Hargreaves and Clandinin, 1987;Bourre et al, 1989), disturbed electroretinographic measurements and visionrelated parameters (Neuringer et al, 1988Bourre et al, 1989Bourre et al, , 1993Uauy et al, 1990Uauy et al, , 1992Birch et al, 1992Birch et al, , 1993, depressed learning ability (Lamptey and Walker, 1978;Yamamoto et al, 1988;Bourre et al, 1989;Enslen et al, 1991;Wainwright et al, 1991), and disturbed behavior and water intake (Reisbick et al, 1992Nakashima et al, 1993). On the other hand, the learning ability of rats was enhanced by both shortterm (Yonekubo et al, 1994) and long-term (Jensen et al, 1996) supplementation of dietary n-3 FAs.…”

Section: Introductionmentioning

confidence: 95%

Replenishment of docosahexaenoic acid in n-3 fatty acid-deficient fetal rats by intraamniotic ethyl-docosahexaenoate administration

1997

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A procedure for intraamniotic ethyl-docosahexaenoate (Et-DHA) administration was used to restore the docosahexaenoic acid (DHA; 22:6 n-3) levels in n-3-deficient fetal rats. The state of deficiency, characterized by a 34% and 60% decrease in DHA content of fetal brain and liver, respectively, was attained by feeding the pregnant dams from day 8 and up to 20 days gestation, with an n-3 linolenic acid-deprived diet. After a single intraamniotic administration of Et-DHA on day 18 or 19, a rapid increase in both fetal brain and liver DHA was achieved. This increase was accompanied by a decrease in the docosapentaenoic acid (DPA; 22:5 n-6) level. After 48 hr following Et-DHA administration, the major phospholipids (PLs) phosphatidylserine (PS), phosphatidylethanolamine (PE), and phosphatidylcholine (PC), together accounting for more than 90% of total lipid phosphorus in sunflower oil (SFO)-treated animals, regained the DHA content to levels similar to control animals in both fetal brain and liver tissues. Unlike brain, however, most of the DHA content in liver PLs was restored by 24 hr, suggesting that the fetal liver may have a higher metabolic turnover. The DHA/DPA ratio was used to assess the degree of DHA correction. Fetal brain PS, PC, and PE ratios following Et-DHA administration grew steadily over a period of 48 hr but reached only approximately 60% of the control levels. Liver PS regained a value similar to the control, while those of PC and PE were 33% and 46% lower than the controls, respectively. Alterations in the PL polar head-group composition were observed following the dietary manipulations and Et-DHA administration. Although the intraamniotic injection is an invasive approach, the ability to rapidly enhance DHA acylation during intrauterine life may hold potential clinical value whenever an indication for DHA deficiency exists.

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Phosphatidylethanolamine methyltransferase: evidence for influence of diet fat on selectivity of substrate for methylation in rat brain synaptic plasma membranes

Cited by 81 publications

References 29 publications

Synthesis of specific fatty acids contributes to VLDL-triacylglycerol composition in humans with and without type 2 diabetes

Synthesis of specific fatty acids contributes to VLDL-triacylglycerol composition in humans with and without type 2 diabetes

Effect of w3 fatty acid on plasma lipids, cholesterol and lipoprotein fatty acid content in NIDDM patients

Replenishment of docosahexaenoic acid in n-3 fatty acid-deficient fetal rats by intraamniotic ethyl-docosahexaenoate administration

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