A comparison of the rates of incorporation of fatty acids during the rapid synthesis in vitro of endogenous triacylglycerols by neuronal nuclei

1983 ◽  
Vol 61 (12) ◽  
pp. 1265-1271 ◽  
Author(s):  
R. Roy Baker ◽  
Huu-yi Chang
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Acyl Transferase ◽  
Rapid Synthesis ◽  
Neuronal Nuclei ◽  
Triacylglycerol Synthesis ◽  
Acid Incorporation ◽  
Fatty Acid Incorporation ◽  
Specific Activities

The incorporation of radioactive palmitate, oleate, linoleate, and arachidonate into endogenous triacylglycerols was followed in vitro using neuronal nuclei (N1) isolated from cerebral cortices of 15-day-old rabbits. Specific rates of incorporation of fatty acids into N1 triacylglycerols were 33–42 times and more than 100 times the corresponding values for cerebral cortex homogenates and microsomal fractions (P3), respectively. Acyl-CoA synthetase specific activities in N1 were 2.2 to 3.2 times the specific rates for fatty acid incorporation into N1 triacylglycerols. Using single fatty acids, N1 acyl-CoA synthetase showed a preference for linoleate which was more highly marked in linoleate–palmitate and linoleate–arachidonate competitions. In fatty acid incorporation into N1 triacylglycerols a preference for linoleate in competition with palmitate was noted; however, there was also a relatively higher utilization of arachidonate shown competitively than was noted in acyl-CoA synthesis. The data suggested that N1 diacylglycerol acyl transferase shows a selectivity for arachidonoyl-CoA in comparison with CoA esters of palmitate or oleate. Molecular class analyses of radioactive triacylglycerol products indicated that native endogenous N1 diacylglycerols bearing arachidonate or fatty acids of equal or higher unsaturation were used preferentially in N1 triacylglycerol synthesis. This preference was significantly decreased when higher levels of endogenous diacylglycerols were produced in N1 following a phospholipase C preincubation.

On the Occurrence of Monoacylglycerol Derivatives in Lipid Metabolism of Chloroplasts

1982 ◽  
Vol 37 (3-4) ◽  
pp. 218-225 ◽  
Author(s):  
Andreas Sauer ◽  
Klaus-Peter Heise
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Lipid Fraction ◽  
Acyl Donor ◽  
Rapid Synthesis ◽  
Acid Incorporation ◽  
Fatty Acid Incorporation ◽  
Acyl Acceptors ◽  
Fatty Acid Species ◽  
Acyl Donors

Abstract The aim of this investigation was to elucidate the rapid synthesis o f monogalactosyl mono­ glycerides and their role as intermediary acyl-acceptors in galactolipid synthesis of spinach chlo­ roplasts. The problem was attacked by studying the incorporation o f sn-[14C]glycerol-3-phosphate and [l-14C]acetate into the lipid fraction o f gently shocked and reconstituted preparations. The data revealed: 1 . a concurrent accumulation o f both monoglycerides and monogalactosyl monoglycerides under acidic incubation conditions, with C16-fatty acid species predominating, 2 . similarities in the fatty acid incorporation of both monoacyllipids, 3. the occurrence o f two isomeric forms viz. 1 -and 2-O-acyl-isomers o f these lipids. Thus, it appears that monogalactosyl monoglycerides are synthesized by galactosylation o f mo­ noglycerides rather than by galactolipase hydrolysis. Both monoacyllipids are likely to be derived from the corresponding lysophosphatidic acids by dephosphorylation. Their fatty acid incorporation pattern therefore may contribute to an under­ standing of the specific esterification o f different fatty acids at the Ct-and exp osition of the gly­ cerol moiety of galactolipids. Analysis o f the specific acylation o f monoglycerides and monogalac­ tosyl monoglycerides as well as the nature of the acyl donors involved in this fatty acid transfer yielded the following observations: 5. The position of the fatty acids within the monoacyllipids seems to depend on whether acyl-ACP or acyl-CoA is the primary acyl donor. 6 . The characteristics of the fatty acid incorporation into monoglycerides and their galactosylated derivatives support the notion that a successive acylation o f sn-glycerol-3-phosphate occurs first in the C2-and then in the Q-position. 7. In contrast, the chain length o f the fatty acids incorporated seems to be determined by such fac­ tors as pH and the concentration o f sn-glycerol-3-phosphate. This observation suggests that these parameters may act by controlling the elongation o f ACP-bound C16-fatty acids to their C18-species.

EFFECT OF ERUCIC ACID ON INCORPORATION OF ACETATE-1-C14 INTO CHOLESTEROL AND FATTY ACIDS

1959 ◽  
Vol 37 (7) ◽  
pp. 803-810 ◽  
Author(s):  
K. K. Carroll
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Erucic Acid ◽  
Cholesterol Metabolism ◽  
Young Male ◽  
Male Rats ◽  
Acetate Incorporation ◽  
Acid Incorporation ◽  
Liver Slices ◽  
Fatty Acid Incorporation

Young male rats were fed synthetic diets containing either no fat or various individual fatty acids for 3 to 4 weeks. They were then killed and the incorporation of acetate-1-C14 into cholesterol and fatty acids was measured in liver slices and in scrapings of intestinal mucosa. Acetate incorporation into cholesterol by liver slices was much greater in animals fed erucic acid than in those fed no fat, palmitic, stearic, oleic, or linoleic acids. A marked differential was not observed in fatty acid incorporation but values tended to be higher on the fat-free and erucic acid diets. Erucic acid did not stimulate acetate incorporation into cholesterol by mucosa and in general mucosa seemed to be less sensitive to changes in diet. The results are discussed in relation to previously observed effects of erucic acid on cholesterol metabolism.

Influence of Kynurenine, Neopterin, Noradrenaline and Pyridoxal-5-Phosphate on Cholesterol and Phospholipid Content and Phospholipid Biosynthesis in vitro

Pteridines ◽  
1993 ◽  
Vol 4 (3) ◽  
pp. 126-130 ◽  
Author(s):  
Vera Rudzite ◽  
Edite Jurika ◽  
Gilbert Reibnegger ◽  
Günter Weiss ◽  
Helmut Wachter ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Fatty Acid ◽  
Incubation Medium ◽  
Tissue Homogenate ◽  
Phospholipid Content ◽  
Phospholipid Biosynthesis ◽  
Acid Incorporation ◽  
Wet Weight ◽  
Fatty Acid Incorporation

Summary Incorporation of fatty acids into phospholipids has been investigated using samples of rat liver tissue homogenate, Krebs-Ringer-phosphate buffer (pH = 7.4) containing 0.3% albumin, fatty acid mixture and glyceroL The addition of L-kynurenine (4 nmol/g wet weight), D-eryhro-neopterin (5 and 30 pmol/g wet weight) and noradrenaline (4 nmol/g wet weight) to incubation medium induced an increase of saturated (palmitic acid) and decrease of poly-unsaturated (linoleic and arachidonic acid) fatty acids incorporation into phospholipids. The increase of saturated fatty acids incorporation into phospholipids was more pronounced after addition of neopterin and noradrenaline to the incubation medium while the decrease of linoleic and arachidonic acid synthesis was stimulated most with kynurenine. Moreover, kynurenine stimulated whereas neopterin depressed the oleic acid incorporation into phospholipids. These changes of fatty acid incorporation into phospholipids were followed by increase of cholesterol content in samples containing kynurenine, neopterin or noradrenalin. In contrast, phospholipid content decreased in samples containing kynurenine or noradrenalin, hut was not altered by supplementation of neopterin. Since the addition of kynurenine and neopterin to incubation medium for isolated fog heart resulted in an increased noradrenaline and decreased pyridoxal-5-phosphate content in the tissue, we also added pyridoxal-5-phosphate (4 nmol/g wet weight) to incubation medium for phospholipid biosynthesis. No change of the fatty acid incorporation into phospholipids as welI as the content of phospholipids and cholesterol in samples was observed.

Control of Fatty Acid Incorporation into Chloroplast Lipids in vitro

1984 ◽  
Vol 39 (6) ◽  
pp. 593-599 ◽  
Author(s):  
Andreas Sauer ◽  
Klaus-Peter Heise
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Lysophosphatidic Acid ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Acid Formation ◽  
Regulatory Function ◽  
Physiological Conditions ◽  
Acid Incorporation ◽  
Fatty Acid Incorporation

1.In isolated chloroplasts which are provided with essential exogenous substrates for glycerolipid biosynthesis (sn-G3P and UDPgal) the incorporation of fatty acids into lipids shows the same pH dependence as the fatty acid synthesis itself with a stromal pH optimum close to 8.5. 2.Furthermore high rates of glycerolipid biosynthesis appear to be accompanied by a preferred oleate incorporation as compared to palmitate. 3.Reinvestigations of the sn-G3P requirement of plastid lysophosphatidic acid formation with rapidly prepared substrate-free chloroplast extracts under approximately physiological conditions reveal a lower specificity of the primary sn-G3P acylation for oleate, as recently found for the fatty acid transfer from purified acyl-ACP fractions on to sn-G3P, catalyzed by purified acyl transferase 1. 4.A comparison of calculated stromal sn-G3P levels under physiological conditions (0.1- 0.3 mᴍ) with those, required for half saturation of the primary acylation reaction either with oleate (Km(sn-G3P) = 0.3 mᴍ) or palmitate (Km (sn-G3P) = 0.6 mᴍ) in chloroplast extracts suggests, that both fatty acids to be involved in lysophosphatidic acid formation within chloroplasts, although oleate would be preferred. 5.The latter observation facilitates the understanding of a palmitate accumulation in chloroplast lipid fractions, induced by increasing sn-G3P concentrations in chloroplast sus­pensions. 6.Although stimulating fatty acid synthesis from acetate in intact chloroplasts, acyl-CoA- synthesizing-conditions (presence of CoA and ATP) in the applied chloroplast extracts appear to inhibit fatty acid incorporation into sn-G3P and thus to exert a regulatory function between the plastidary and extraplastidary glycerolipid biosynthesis.

scholarly journals Different functions of intestinal and liver-type fatty acid-binding proteins in intestine and in whole body energy homeostasis

2011 ◽  
Vol 300 (5) ◽  
pp. G803-G814 ◽  
Author(s):  
William Stacy Lagakos ◽  
Angela Marie Gajda ◽  
Luis Agellon ◽  
Bert Binas ◽  
Victor Choi ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Null Models ◽  
Dietary Fatty Acids ◽  
Fat Free Mass ◽  
Whole Body ◽  
Fatty Acid Binding Proteins ◽  
Fatty Acid Binding ◽  
Triacylglycerol Synthesis

It has long been known that mammalian enterocytes coexpress two members of the fatty acid-binding protein (FABP) family, the intestinal FABP (IFABP) and the liver FABP (LFABP). Both bind long-chain fatty acids and have similar though not identical distributions in the intestinal tract. While a number of in vitro properties suggest the potential for different functions, the underlying reasons for expression of both proteins in the same cells are not known. Utilizing mice genetically lacking either IFABP or LFABP, we directly demonstrate that each of the enterocyte FABPs participates in specific pathways of intestinal lipid metabolism. In particular, LFABP appears to target fatty acids toward oxidative pathways and dietary monoacylglycerols toward anabolic pathways, while IFABP targets dietary fatty acids toward triacylglycerol synthesis. The two FABP-null models also displayed differences in whole body response to fasting, with LFABP-null animals losing less fat-free mass and IFABP-null animals losing more fat mass relative to wild-type mice. The metabolic changes observed in both null models appear to occur by nontranscriptional mechanisms, supporting the hypothesis that the enterocyte FABPs are specifically trafficking their ligands to their respective metabolic fates.

A comparison of the acylation of 1-acyl-sn-glycero-3-phosphoinositol and 1-acyl-sn-glycero-3-phosphocholine in neuronal nuclei in vitro using radioactive arachidonate and oleate

1986 ◽  
Vol 64 (1) ◽  
pp. 1-7 ◽  
Author(s):  
R. Roy Baker ◽  
Huu-Yi Chang
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Nuclear Fraction ◽  
Maximal Rate ◽  
Low Concentration ◽  
Neuronal Nuclei ◽  
Low Concentrations ◽  
High Concentrations

A neuronal nuclear fraction (N1) was isolated from cerebral cortices of 15-day-old rabbits. Samples of N1 were incubated with a radioactive fatty acid ([3H]arachidonate or [14C]oleate), acylation cofactors, and 1-acyl-sn-glycero-3-phosphoinositol (1-acyl-GPI) or 1-acyl-sn-glycero-3-phosphocholine (1-acyl-GPC). In competition studies, both radioactive fatty acids were incubated with one lysophospholipid or the two lysophospholipids were incubated with one radioactive fatty acid. Using [3H]arachidonate and one lysophosphoglyceride, a maximal rate of incorporation into phosphatidylinositol (PI) was found at a relatively low concentration of 1-acyl-GPI (10 μM), while increasing rates of incorporation into phosphatidylcholine (PC) were seen with increasing concentrations of 1-acyl-GPC (to 65 μM). At low concentrations of lysophosphoglyceride (≤ 25 μM) the rate of arachidonate incorporation into PI greatly exceeded rates of arachidonate incorporation into PC. This higher rate of arachidonate incorporation into PI was also seen in incubations where both lysophospholipids were present. For oleate, greater rates of incorporation into PC were found in comparison with rates of labelling of PI in assays using relatively high concentrations of one or both lysophospholipids. When comparing arachidonate and oleate, in assays with one or both fatty acids, the polyunsaturate showed at least threefold higher rates of incorporation into PI. For PC labelling higher rates of arachidonate incorporation were evident at the higher concentrations of 1-acyl-GPC and the superiority over oleate was not as marked as that seen in PI labelling.

EFFECT OF ERUCIC ACID ON INCORPORATION OF ACETATE-1-C14 INTO CHOLESTEROL AND FATTY ACIDS

1959 ◽  
Vol 37 (1) ◽  
pp. 803-810 ◽  
Author(s):  
K. K. Carroll
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Erucic Acid ◽  
Cholesterol Metabolism ◽  
Young Male ◽  
Male Rats ◽  
Acetate Incorporation ◽  
Acid Incorporation ◽  
Liver Slices ◽  
Fatty Acid Incorporation

Young male rats were fed synthetic diets containing either no fat or various individual fatty acids for 3 to 4 weeks. They were then killed and the incorporation of acetate-1-C14 into cholesterol and fatty acids was measured in liver slices and in scrapings of intestinal mucosa. Acetate incorporation into cholesterol by liver slices was much greater in animals fed erucic acid than in those fed no fat, palmitic, stearic, oleic, or linoleic acids. A marked differential was not observed in fatty acid incorporation but values tended to be higher on the fat-free and erucic acid diets. Erucic acid did not stimulate acetate incorporation into cholesterol by mucosa and in general mucosa seemed to be less sensitive to changes in diet. The results are discussed in relation to previously observed effects of erucic acid on cholesterol metabolism.

Pattern of Incorporation of 32P into the Phospholipids of the Rat Tapeworm Hymenolepis diminuta

1971 ◽  
Vol 49 (11) ◽  
pp. 1209-1212 ◽  
Author(s):  
R. A. Webb ◽  
D. F. Mettrick
Keyword(s):  
Fatty Acid ◽  
Phosphatidic Acid ◽  
De Novo ◽  
Hymenolepis Diminuta ◽  
De Novo Synthesis ◽  
Major Pathway ◽  
Acid Incorporation ◽  
Fatty Acid Incorporation

The incorporation of 32P-orthophosphate into the phospholipids of H. diminuta was followed for up to 4 h in vitro. The rates and patterns of incorporation of 32P into phosphatidc acid, phosphoinositide, phosphatidylserine, lecithin, lysolecithin, and phosphatidylethanolamine plus cardiolipin indicated that H. diminuta possesses mechanisms for the de novo synthesis of these phospholipids. The major pathway utilized by H. diminuta in fatty acid incorporation was via phosphatidic acid.

Impairment of Lipid Metabolism Due to Deficiency of Pyridoxal-5-phosphate and/or Activated Immune system: its Interpretation

Pteridines ◽  
2000 ◽  
Vol 11 (4) ◽  
pp. 107-120 ◽  
Author(s):  
Vera Rudzite ◽  
Edite Jurika ◽  
Matthias Jäger ◽  
Dietmar Fuchs
Keyword(s):  
Cell Cycle ◽  
Fatty Acid ◽  
Immune System ◽  
Membrane Fluidity ◽  
Incubation Medium ◽  
Phospholipid Biosynthesis ◽  
P Deficiency ◽  
Acid Incorporation ◽  
Fatty Acid Incorporation

Abstract Impairment of lipid metabolism due to excess metabolite accumulation induced by pyridoxal-5-phosphate (P-5-P)-deficiency and/or stimulated immune system has been studied and interpreted. Decreased amounts of phospholipids as well as deviations in phospholipid classes and fatty acid composition of phospholipids have been demonstrated due to kynurenine accumulation in the blood of P-5-P-deficient cardiovascular patients and white rats as well as in cardiovascular patients with activated immune system identified by an increased neopterin concentration in the blood (dilated cardiomyopathy). The addition of P-5-P to the incubation medium for phospholipid biosynthesis in vitro did not change fatty acid incorporation into phospholipids, whereas it normalised fatty acid incorporation into phospholipids in liver homogenates received from P-5-P-deficient rats: The addition of kynurenine, neopterin and noradrenalin (accumulated m isolated heart tissue after addition of kynurenine and neopterin to incubation medium for isolated heart) to incubation medium for phospholipid biosynthesis in vitro induced an increase of saturated and a decrease of polyunsaturated fatty acid incorporation into phospholipids. These changes in fatty acid incorporation into phospholipids were followed by increased cholesterol concentrations in samples and an increased cholesterol/phospholipid ratio. Our results suggest that these changes in lipids are characteristic for decreased membrane fluidity, depressed cell cycle and lowered possibility of phospholipids to keep cholesterol in solution. P-5-P-deficiency is also accompanied with excess accumulation of homocysteine in the blood. The addition of L-homocysteine to the incubation medium for phospholipid biosynthesis in vitro was followed by inverse changes in fatty acid incorporation into phospholipids when compared with kynurenine, neopterin and noradrenalin. L-homocysteine induced a decrease of saturated and an increase of polyunsaturated fatty acid incorporation into phospholipids. The cholesterol concentration decreased in samples and the cholesterol/ phospholipid ratio decreased, too . These findings suggest that changes in lipids induced by L-homocysteine are characteristic for increased membrane fluidity and stimulated cell cycle. In this study, we have observed a similar effect to L-homocysteine effect when L-homocysteine, L-tryptophan and 5,6,7,8-tetrahydrobiopterin were added to the incubation medium for phospholipid biosynthesis in vitro. The comparison of our results with data from the literature allows to suggest that excess metabolite accumulation due to activated formation and inactivated catabolism of it plays a significant role in quantitative and qualitative changes of lipids, especially phospholipids, and therefore participates in the regulation of membrane fluidity, cell cycle of normal and malignant cells as well as in keeping cholesterol in the state of solution.

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