Effect of geometry and position of ethylenic bond upon acyl coenzyme A-cholesterol-O-acyltransferase

Sgoutas, Demetrios S.

doi:10.1021/bi00810a024

Cited by 57 publications

(19 citation statements)

References 29 publications

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“…On the other hand, the percentages of the total 18:2 acids in perfusate triglyceride and choles terol ester were significantly lower on perfus ing the »-acid isomer than on perfusing the ccacid(40.3 ± 1.4 vs. 49.3 ± 0.6% for triglycer ide and 26.0 ± 0.5 vs. 32.3 ± 0.7% for choles terol ester, these differences being statistically significant). The decrease in the incorporation of »-acid into the triglyceride was consistent with previous reports [1,4] and was in good agreement with the observation that tram-fat ty acids repress the hepatic microsomal ACAT activities in vitro [13]. Thus, the reduced se cretion of triglyceride and cholesterol ester by the livers perfused with tram-fatty acid was associated with a concomitant decrease in the percentages of total 18:2 acids.…”

Section: Resultssupporting

confidence: 92%

“…There is a possibility of an increased incorporation of exogenous fatty acids into triglyceride and cholesterol ester at the expense of their oxidation [12], suggesting a reciprocal response in ketogenesis and lipid secretion in the livers of rats fed the cholester ol-enriched diet. Tra/w-fatty acids repress the hepatic microsomal ACAT activity in vitro [13], in addition to its adverse effect on key enzyme activities in fatty acid metabolism in the liver [14,15]. Thus, it is of interest to examine whether the di-tram-fatty acids as compared to the m-counterparts also exert their inverse effect on ketogenesis and lipid secretion in the livers of rats fed the cholester ol-enriched diet.…”

Section: Introductionmentioning

confidence: 99%

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Differential Effects of Geometrical Isomers of Octadecadienoic Acids on Ketogenesis and Lipid Secretion in the Livers from Rats Fed a Cholesterol-Enriched Diet

Fukuda¹,

Etoh²,

Wada³

et al. 1995

Ann Nutr Metab

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The effect of ciscis (cc)- and trans, trans (tt)-9,12-octadecadienoic (18:2) acids on ketogenesis and lipid secretion was compared in isolated perfused livers from cholesterol-fed rats. The hepatic uptake of 18:2 acids was comparable in both isomers. The livers perfused with cc-18:2 acid in comparison with those perfused without fatty acid substrate produced approximately 4-fold more ketone bodies accompanying the rise of the β-hydroxybutyrate:acetoacetate ratio, while the tt-acid isomer further increased these parameters. The hepatic secretion rates of triglyceride and phospholipid as well as cholesterol were all elevated on perfusing the cc-18:2 acid as compared to without fatty acid. In contrast, the rates observed with the tt-18:2 acid isomer except for phospholipid were intermediate, indicating a reciprocal response in ketogenesis and lipid secretion by the trans isomer. The rate of incorporation of trans-fatty acid into perfusate triglyceride and cholesterol ester were lower than cis-acid, but vice versa into perfusate phospholipids. On the other hand, the effects of trans-fatty acid on the concentration and composition of hepatic lipids were less clear. These results emphasize the differential effect of geometrical isomers of the 18:2 acids on oxidation and esterification even in the livers containing a high level of cholesterol.

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Section: Resultssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Differential Effects of Geometrical Isomers of Octadecadienoic Acids on Ketogenesis and Lipid Secretion in the Livers from Rats Fed a Cholesterol-Enriched Diet

Fukuda¹,

Etoh²,

Wada³

et al. 1995

Ann Nutr Metab

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“…The fatty acid specificity of rat liver ACAT in our study is similar to that observed previously with the exception of linoleic acid. Previous studies (19,34), found an esterification rate for linoleoyl-CoA between 15 and 40%, the rate of oleate, while in our experiments they were equivalent. There are several possible explanations for the observed differences.…”

Section: Resultssupporting

confidence: 51%

Functional Expression of a cDNA to Human Acyl-coenzyme A:Cholesterol Acyltransferase in Yeast

Yang¹,

Cromley

Wang

et al. 1997

Journal of Biological Chemistry

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“…trans Fatty acids affect membrane fluidity (31) and can interfere with cellular fatty acid metabolism (32). They repress hepatic sterol-O-acyltransferase activity in vitro (33) and determine partition of fatty acids between oxidation and esterification by affecting key enzymes in hepatic fatty acid metabolism (6). Some trans fatty acids interfere with essential fatty acid metabolism (34), eg, via platelet aggregation (35) and by decreasing prostaglandin concentrations (36).…”

Section: Discussionmentioning

confidence: 99%

“…It would be interesting to study the acute postprandial triacylglycerol response after an oral fat load with either c-or t-18:1-enriched fat emulsions containing a metabolic marker for chylomicrons in humans. An additional effect of t-18:1⌬9 on LDL cholesterol is more likely to occur at the concentration of LDL-receptor expression or at the level of VLDL secretion (29,33).…”

Section: Discussionmentioning

confidence: 99%

Lipoprotein secretion by intestinal Caco-2 cells is affected differently by trans and cis unsaturated fatty acids: effect of carbon chain length and position of the double bond1

Greevenbroek¹,

Robertus-Teunissen²,

Erkelens³

et al. 1998

The American Journal of Clinical Nutrition

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The effects of trans fatty acids on intestinal lipoprotein secretion were determined in polarized Caco-2 cells. Palmitic acid (16:0), palmitoleic acid (c-16:1⌬9), and palmitelaidic acid (t-16:1⌬9), as well as stearic acid (18:0), oleic acid (c-18:1⌬9), c-vaccenic acid (c-18:1⌬11), elaidic acid (t-18:1⌬9), and t-vaccenic acid (t-18:1⌬11) were studied. Compared with 18:0 (control), c-and t-18:1⌬9 increased triacylglycerol secretion (2.7-and 3.6-fold, respectively) as well as apolipoprotein (apo) B-48 and apo B-100 secretion (both 1.6-fold compared with 18:0); c-and t-18:1⌬11 caused a modest 1.7-fold increase in triacylglycerol secretion with no significant effect on secretion of apo B. Thus, the position of the double bond in the 18:1 isomers, but not its geometrical configuration, affected lipoprotein secretion by Caco-2 cells. In contrast, the effects of the geometrical isomers (cis and trans) of C 16 fatty acids were not comparable: t-16:1⌬9 did not affect triacylglycerol and apo B secretion (compared with 16:0, as control) whereas c-16:1⌬9 was a potent stimulator of secretion of triacylglycerol (2.4-fold higher than 16:0), apo B-48 (1.3-fold higher than 16:0), and apo B-100 (1.5-fold higher than 16:0). We conclude that the carbon chain length of fatty acids, as well as the position of double bonds and their stereochemical configuration, are important determinants of the unique effects of various species of dietary trans fatty acids on lipoprotein secretion and composition in Caco-2 cells.Am J Clin Nutr 1998;68:561-7. KEY WORDSIntestine, apolipoprotein B, Caco-2 cells, cis fatty acids, trans fatty acids, lipoproteins, diet, triacylglycerol, chylomicrons, in vitro study INTRODUCTIONSynthesis of chylomicrons in the enterocyte represents the initial step in the cascade of metabolic events that connects dietary fat intake with plasma lipid and lipoprotein profiles and the possible development of coronary artery disease (CAD) (1, 2). Postprandial lipemia is determined by the contribution of chylomicrons containing triacylglycerol from dietary sources as well as that of VLDLs that carry liver-derived triacylglycerols. Various dietary fatty acids are known to have specific effects on plasma triacylglycerol concentrations (3, 4), reflecting interference with intestinal chylomicron assembly and metabolism. One specific class of dietary fatty acids that has received growing attention in the past decades is that of the trans fatty acids. trans Fatty acids are known to cause changes in plasma lipids and lipoprotein phenotypes, but the mechanisms involved are unknown. The major dietary sources of trans fatty acids are partly hydrogenated vegetable oils, mainly elaidic acid (t-18:1⌬9). Additional sources are animal and dairy fats [palmitelaidic acid (t-16:1⌬9) and tvaccenic acid (t-18:1⌬11)] and partly hydrogenated fish oils (very-long-chain trans fatty acids, ie, > C 22 ). Because humans cannot synthesize trans fatty acids (5, 6), all trans fatty acids are derived from nutritional sources. Dietary trans fatty acids ...

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Effect of geometry and position of ethylenic bond upon acyl coenzyme A-cholesterol-O-acyltransferase

Cited by 57 publications

References 29 publications

Differential Effects of Geometrical Isomers of Octadecadienoic Acids on Ketogenesis and Lipid Secretion in the Livers from Rats Fed a Cholesterol-Enriched Diet

Differential Effects of Geometrical Isomers of Octadecadienoic Acids on Ketogenesis and Lipid Secretion in the Livers from Rats Fed a Cholesterol-Enriched Diet

Functional Expression of a cDNA to Human Acyl-coenzyme A:Cholesterol Acyltransferase in Yeast

Lipoprotein secretion by intestinal Caco-2 cells is affected differently by trans and cis unsaturated fatty acids: effect of carbon chain length and position of the double bond1

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