Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “OLEIC ACID”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,441 records · Page 80Linked to original sources
PubMed2004

Botanical solvents.

Botanical, or plant-derived, solvents such as turpentine, pine oils, and various essential oils are used as environmentally acceptable alternatives to traditional solvents and degreasing agents. This article focuses on three lesser-known botanical solvents: limonene, oleic acid, and linoleic acid. Although data are limited, limonene, linoleic acid, and oleic acid are likely of low toxicity. Mild skin irritation may occur from exposure to these compounds, and oxidation products of limonene may produce dermal sensitization. Limonene, and possibly linoleic and oleic acids, may have irritative and bronchoconstrictive airway effects; however, data are scant and more studies are required.

Cyclohexenes↗
PubMed1988

Membrane attachment activates dnaA protein, the initiation protein of chromosome replication in Escherichia coli.

ADP and ATP are tightly bound to dnaA protein and are crucial to its function in DNA replication; the exchange of these nucleotides is effected specifically by the acidic phospholipids (cardiolipin and phosphatidylglycerol) present in Escherichia coli membranes [Sekimizu, K. & Kornberg, A. (1988) J. Biol. Chem. 263, 7131-7135]. We now find that phospholipids derived from membranes lacking an unsaturated fatty acid (e.g., oleic acid) are unable to promote the exchange. This observation correlates strikingly with the long-known effect of 3-decynoyl-N-acetylcysteamine, a "suicide analog" that prevents initiation of a cycle of replication in E. coli by inhibiting the synthesis of oleic acid, an inhibition that can be overcome by providing the cells with oleic acid. Profound influences on the specific binding of dnaA protein to phospholipids by temperature, the content of unsaturated fatty acids, and the inclusion of cholesterol can be explained by the need for the phospholipids to be in fluid-phase vesicles. These findings suggest that membrane attachment of dnaA protein is vital for its function in the initiation of chromosome replication in E. coli.

Adenosine Triphosphate↗
PubMed1989

[The study of thromboxane A2 and prostacyclin in oleic acid-induced lung injury in dogs].

Acute lung injury was produced by intravenous injection of oleic acid. After oleic acid injection, PaO2 was decreased, dogs were involved in respiratory distress. Histological examination indicated aggregation of leukocytes in microvasculature, interstitial and intraalveolar pulmonary edema and congestion in the lung. Using radioimmunoassay technique, changes in arterial and venous plasma levels of stable metabolite of thromboxane A2 (TXA2), thromboxane B2 (TXB2) have been observed. After oleic acid administration, plasma 6-keto-PGF1alpha level was markedly elevated with two peaks. 6-keto-PGF1alpha level in arteries was higher in concentration than in veins. It was suggested that the lung might synthesis a great quantity of prostacyclin entering the systemic circulation. TXB2 was markedly elevated in plasma, which was more in veins than in arteries. A significant arteriovenous difference suggests that there might be extrapulmonary sources contributing to the elevation of plasma TXB2 in oleic acid induced lung injury in dogs. After treatment with large dose of anisodamine (654-2), platelets and leukocytes aggregation could be inhibited as well as the synthesis of TXA2 and prostacyclin. 654-2 might play a role of cyclo-oxygenase inhibitor. It was suggested that 654-2 reduce synthesis of the precursors of TXA2 and prostacyclin, reduce pulmonary edema and might be a therapeutical effect to lung injury.

6-Ketoprostaglandin F1 alpha↗
PubMed2003

Influence of triacylglycerol structure on the postprandial response of factor VII to stearic acid-rich fats.

BACKGROUND: The consumption of a synthetic, randomized, stearic acid-rich triacylglycerol results in decreased postprandial lipemia and activated factor VII (FVII:a) compared with cocoa butter (a nonrandomized, symmetrical, stearic acid-rich triacylglycerol). It was hypothesized that this difference is a consequence of the differences in structure between the 2 triacylglycerols. OBJECTIVE: The objective was to test whether the consumption of randomized cocoa butter decreases postprandial lipemia and FVII:a. DESIGN: A randomized crossover trial with 17 male subjects compared the effects of meals containing 50 g fat provided as a symmetrical (cocoa butter) or an asymmetrical (randomized cocoa butter) triacylglycerol on postprandial changes in lipids, chylomicron composition, and FVII:a. RESULTS: After randomization, the postprandial area under the curve for plasma triacylglycerol decreased by 41% (P < 0.01). At 3 h the plasma concentrations of triacylglycerol, palmitic acid, stearic acid, and oleic acid were 26%, 18%, 34%, and 19% lower, respectively. The proportion of oleic acid in the sn-2 position of the chylomicron triacylglycerol was reduced from 67.4 mol% to 35.9 mol% and resulted in an increase in the proportion of stearic acid in the sn-2 position from 9.2 mol% to 25.4 mol%. FVII:a did not increase 6 h after consumption of the randomized cocoa butter (: 1.2; 95% CI: -2.7, 4.6 U/L) but increased significantly (: 7.7; 95% CI: 2.5,12.9 U/L) 6 h after consumption of the unrandomized cocoa butter. CONCLUSIONS: Symmetrical stearic acid-rich triacylglycerol with oleic acid in the sn-2 position appears to be absorbed more rapidly than is asymmetrical triacylglycerols with long-chain saturated fatty acids in the sn-2 position, which leads to activation of FVII.

Adult↗
PubMed1985

Proton-induced fusion of oleic acid-phosphatidylethanolamine liposomes.

Liposomes composed of oleic acid and phosphatidylethanolamine (3:7 mole ratio) aggregate, become destabilized, and fuse below pH 6.5 in 150 mM NaCl. Fusion is monitored by (i) the intermixing of internal aqueous contents of liposomes, utilizing the quenching of aminonaphthalene-3,6,8-trisulfonic acid (ANTS) by N,N'-p-xylylenebis(pyridinium bromide) (DPX) encapsulated in two separate populations of vesicles, (ii) a resonance energy transfer assay for the dilution of fluorescent phospholipids from labeled to unlabeled liposomes, (iii) irreversible changes in turbidity, and (iv) quick-freezing freeze-fracture electron microscopy. Destabilization is followed by the fluorescence increase caused by the leakage of coencapsulated ANTS/DPX or of calcein. Ca2+ and Mg2+ also induce fusion of these vesicles at 3 and 4 mM, respectively. The threshold for fusion is at a higher pH in the presence of low (subfusogenic) concentrations of these divalent cations. Vesicles composed of phosphatidylserine/phosphatidylethanolamine or of oleic acid/phosphatidylcholine (3:7 mole ratio) do not aggregate, destabilize, or fuse in the pH range 7-4, indicating that phosphatidylserine and phosphatidylcholine cannot be substituted for oleic acid and phosphatidylethanolamine, respectively, for proton-induced membrane fusion. Freeze-fracture replicas of oleic acid/phosphatidylethanolamine liposomes frozen within 1 s of stimulation with pH 5.3 display larger vesicles and vesicles undergoing fusion, with membrane ridges and areas of bilayer continuity between them. The construction of pH-sensitive liposomes is useful as a model for studying the molecular requirements for proton-induced membrane fusion in biological systems and for the cytoplasmic delivery of macromolecules.

Calcium↗
PubMed1992

Role of endogenous secretin and cholecystokinin in intraduodenal oleic acid-induced inhibition of gastric acid secretion in rats.

We investigated a possible role of endogenous secretin and cholecystokinin (CCK) in inhibition of gastric acid secretion induced by intraduodenal administration of oleic acid in rats. Intraduodenal administration of oleic acid emulsion in a dose of 1 mmol/hr resulted in significant inhibition of gastric acid secretion stimulated by intravenous infusion of pentagastrin (0.3 micrograms/kg/hr), and this was accompanied by an increase in the plasma concentration of both secretin and CCK, from 1.2 +/- 0.08 pM and 20.6 +/- 1.2 pM to 4.3 +/- 0.18 pM and 31.6 +/- 0.9 pM, respectively (P less than 0.001). Intravenous infusion of secretin (0.05 CU/kg/hr) inhibited pentagastrin-stimulated gastric acid secretion, but CCK-8 (0.03 micrograms/kg/hr) failed, although intravenous infusion of secretin and CCK in those doses produced plasma levels comparable to the levels achieved in response to oleic acid administration. Furthermore, the oleic acid-induced suppression of gastric acid secretion was blocked significantly by intravenous injection of rabbit anti-secretin serum (0.1 ml), but not by intravenous infusion of a CCK-receptor antagonist, CR 1409 (5 mg/kg/hr). Thus, the results of this study indicate that endogenous secretin rather than CCK is involved in the hormonal mechanism regulating the inhibition of gastric acid secretion by intestinal fat in rats.

Animals↗
PubMed1995

Lipoprotein concentrations in normolipidemic males consuming oleic acid-rich diets from two different sources: olive oil and oleic acid-rich sunflower oil.

The effects on plasma lipid concentrations of two oleic acid-rich diets, prepared with two different plant oils--olive oil and sunflower oil high in monounsaturated fatty acids (MUFAs)-- were compared with a National Cholesterol Education Program (NCEP) I diet. Twenty-one healthy, normolipidemic, young males consumed an NCEP-I diet (30% of energy as fat) during a 25-d period. Subjects were then assigned to two 4-wk study periods, according to a randomized, crossover design. Group one was placed on an olive oil-enriched diet (40% fat, 22% MUFAs), followed by a 4-wk period of a sunflower oil-enriched diet (40% fat, 22% MUFAs). In group two, the order of the diets was reversed. Both MUFA dietary periods resulted in an increase in high-density-lipoprotein (HDL) cholesterol (7% for the olive oil diet and 4% for the sunflower oil diet) and in apolipoprotein (apo) A-I (9% for both) compared with the NCEP-I diet. Low-density-lipoprotein (LDL) cholesterol and apo B concentrations (x +/- SEM) were lower (P < 0.05) during the sunflower oil diet (2.40 +/- 0.11 mmol/L, 0.85 +/- 0.04 mg/L) than during the olive oil diet (2.64 +/- 0.15 mmol/L, 0.93 +/- 0.05 mg/L). No significant differences were observed in these variables between the sunflower oil and NCEP-I (2.48 +/- 0.13 mmol/L, 0.89 +/- 0.04 mg/L) diets.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1979

Brain specific creatine kinase isoenzyme behavior in rat serum after bile acid, sodium oleate and albumin injection.

In this investigation we have shown that severe liver disease with cerebral involvement can be followed by the presence of BB creatine kinase isoenzyme in serum. Groups of rats were injected with a bile acid mixture, oleic acid, albumin and normal saline respectively. Bile acids or/and oleic acid induced BB isoenzyme to leak from central nervous tissue and this can be measured in serum. Albumin binding prevented this leakage. The experiments support our hypothesis, based on biochemical findings in human liver failure, that detergent and surface activity properties of the above mentioned components are able to produce this specific brain isoenzyme leakage.

Alanine Transaminase↗
PubMed1991

Arachidonic acid and docosahexaenoic acid are increased in human colorectal cancer.

Increased arachidonic acid concentrations in experimental rodent colonic cancer have been described recently. In humans, a reduced erythrocyte stearic acid to oleic acid ratio has been reported in patients with colorectal cancer and it has been proposed that similar changes exist in the cancer tissue. The long chain fatty acids in the cancers of 15 patients with colorectal cancer were measured and compared with values in the unaffected mucosa. The values were expressed as mean (SD) mg fatty acid/g tissue and compared by analysis of variance. In the cancer tissue arachidonic acid was increased (0.703 (0.109) mg/g v 0.603 (0.127) mg/g, p less than 0.05) as was docosahexaenoic acid (0.211 (0.066) mg/g v 0.148 (0.039) mg/g, p less than 0.001). In contrast, the stearic acid to oleic acid ratio in the cancer tissue was increased rather than decreased, as previously suggested (0.36 (0.05) v 0.29 (0.7), p less than 0.01). Increased arachidonic acid and docosahexaenoic acid concentrations may be related to reduced lipid peroxidation, which is a feature of rapidly growing cells. Alternatively, the increased arachidonic acid values could be due to enhanced desaturase activity upon linoleic and linolenic acid, leading perhaps to increased formation of prostaglandins and other lipoxygenase products.

Aged↗
PubMed2004

Antifungal activities of four fatty acids against plant pathogenic fungi.

The effect of the fatty acids linolenic acid, linoleic acid, erucic acid and oleic acid on the growth of the plant pathogenic fungi Rhizoctonia solani, Pythium ultimum, Pyrenophora avenae and Crinipellis perniciosa were examined in in vitro studies. Linolenic and linoleic acids exhibited activity against all of the fungi. However, whereas linolenic acid reduced mycelial growth of R. solani and C. perniciosa at 100 microM, the concentration had to be increased to 1000 microM before any effect on mycelial growth of P. ultimum and P. avenae was observed. Linoleic acid only reduced mycelial growth of R. solani, P. ultimum and P. avenae at 1000 microM, but led to a significant reduction in growth of C. perniciosa at 100 microM. In contrast, oleic acid had no significant effect on growth of R. solani or P. avenae, but gave significant reductions in mycelial growth of P. ultimum at 100 microM and reduced growth of C. perniciosa significantly at 1000 microM. All of the fatty acids reduced biomass production by all of the fungi significantly in liquid culture when added to the media at 100 microM. Erucic acid had no effect on fungal growth at any concentration examined. The antifungal activities exhibited by linolenic, linoleic and oleic acids may be useful in the search for alternative approaches to controlling important plant pathogens, such as those examined in this study.

Ascomycota↗
PubMed2006

Structured triglycerides containing caprylic (8:0) and oleic (18:1) fatty acids reduce blood cholesterol concentrations and aortic cholesterol accumulation in hamsters.

The effects of structured triglycerides containing one long chain fatty acid (oleic acid, C18:1) and one short chain saturated fatty acid (caprylic acid, 8:0) on lipidemia, liver and aortic cholesterol, and fecal neutral sterol excretion were investigated in male Golden Syrian hamsters fed a hypercholesterolemic regimen consisting of 89.9% commercial ration to which was added 10% coconut oil and 0.1% cholesterol (w/w). After 2 weeks on the HCD diet, the hamsters were bled, following an overnight fast (16 h) and placed into one of three dietary treatments of eight animals each based on similar plasma cholesterol levels. The hamsters either continued on the HCD diet or were placed on diets in which the coconut oil was replaced by one of two structured triglycerides, namely, 1(3),2-dicaproyl-3(1)-oleoylglycerol (OCC) or 1,3-dicaproyl-2-oleoylglycerol (COC) at 10% by weight. Plasma total cholesterol (TC) in hamsters fed the OCC and COC compared to the HCD were reduced 40% and 49%, respectively (P<0.05). Similarly, hamsters fed the OCC and COC diets reduced their plasma nonHDL cholesterol levels by 47% and 57%, respectively (P<0.05), compared to hamsters fed the HCD after 2 weeks of dietary treatment. Although hamsters fed the OCC (-26%) and COC (-32%) had significantly lower plasma HDL levels compared to HCD, (P<0.05), the plasma nonHDL/HDL cholesterol ratio was significantly lower (P<0.05) compared to the HCD for the OCC-fed (-27%) and the COC-fed (-38%) hamsters, respectively. Compared to the HCD group, aortic esterified cholesterol was 20% and 53% lower for the OCC and COC groups, respectively, with the latter reaching statistical significance, P<0.05. In conclusion, the hamsters fed the structured triglyceride oils had lower blood cholesterol levels and lower aortic accumulation of cholesterol compared to the control fed hamsters.

Animals↗
PubMed1995

Pentoxifylline prevents a decrease in arterial oxygen tension in oleic acid-induced lung injury.

OBJECTIVES: a) To determine whether pentoxifylline has a preventive effect on the decrease in PaO2 that is caused by oleic acid, and whether pentoxifylline facilitates normalization of PaO2 from the decreased state. b) To examine whether pentoxifylline can attenuate an increase in pulmonary vascular permeability that is induced by oleic acid. DESIGN: Prospective trial. SETTING: University laboratory. SUBJECTS: a) A total of 48 guinea pigs (700 to 1100 g) for blood gas analysis. b) A total of 28 guinea pigs (390 to 670 g) for measurement of pulmonary vascular permeability. INTERVENTIONS: a) For blood gas analysis, the guinea pigs were mechanically ventilated. Oleic acid (15 microL/kg) was injected into the guinea pigs to decrease PaO2. Pentoxifylline (5 or 20 mg/kg) was administered 40 or 3 mins before oleic acid injection or 13 mins after oleic acid injection. b) For measurement of pulmonary vascular permeability, the guinea pigs were anesthetized with pentobarbital and catheterized via the external jugular vein for drug administration. Pentoxifylline (20 mg/kg) plus Evans blue (30 mg/kg) or theophylline (20 mg/kg) plus Evans blue (30 mg/kg) were administered at 40- and 1-min intervals before oleic acid (15 microL/kg) injection, respectively. Perfusion with saline was performed through the aorta 90 mins after the oleic acid injection. The airways were removed and separated into the trachea, the main bronchus, the proximal bronchus, and the distal bronchus. Evans blue was extracted from the airways with formamide for 18 hrs and measured. MEASUREMENTS AND MAIN RESULTS: a) We measured PaO2, PaCO2, and pH, and recorded airway pressure and systemic blood pressure at 15, 10, and 5 mins before oleic acid injection and at 6, 10, 15, 35, 55, and 75 mins after oleic acid injection. Compared with the control groups, a decrease in PaO2 by oleic acid was significantly prevented when pentoxifylline (5 or 20 mg/kg) was administered 40 mins before oleic acid injection. However, a decrease in PaO2 by oleic acid was not significantly reduced when pentoxifylline was administered 3 mins before oleic acid injection. Pentoxifylline administered 13 mins after oleic acid injection did not affect the recovering course of PaO2 significantly. b) An increase in pulmonary vascular permeability by oleic acid was significantly attenuated by both pentoxifylline and theophylline. The effect of theophylline was significantly stronger than the effect of pentoxifylline in the main bronchi. The effect of theophylline was not significantly different from the effect of pentoxifylline in other areas. CONCLUSION: Pentoxifylline is a noteworthy drug that could be a candidate as a therapy to help prevent hypoxemia in lung injuries that share a common mechanism with oleic acid-induced lung injury.

Airway Resistance↗
PubMed1988

Effect of fatty acid administration on plasma thyroid hormones in the domestic fowl.

In birds a severe stress is associated with a reduction in concentrations of plasma thyroxine. Studies in man and the rat have demonstrated that severe illness is associated with an increase in serum concentrations of free fatty acids, notably oleic acid, and that they are associated with a reduction in concentrations of serum thyroxine (T4) and/or triiodothyronine (T3). Since stress is associated with increased fatty acids in birds, we have, in the present study, examined the role of oleic acid and another polyunsaturated fatty acid, arachidonic acid, on thyroid function tests (plasma thyroxine, triiodothyronine, and T3 resin uptake (RT3U) index) and on the thyroidal response to exogenous thyroid-stimulating hormone (TSH) in the domestic fowl. In the first study we observed that the iv administration of arachidonic (10 mg/kg) or oleic acid (15 mg/kg) to groups of 10-week-old cockerels (six per group) was associated with a significant reduction in concentrations of plasma T4, whereas there was little change in saline-injected controls. However, administration of fatty acids to chickens was not associated with a significant change in RT3U index or in the levels of plasma T3. In the second study, groups of animals (n = 6) were injected with bovine TSH (0.5 IU/kg, im) or saline 2.5 hr after the fatty acid injection and blood samples were obtained at -2.5 to 24 hr after the TSH injection. A similar progressive increase in serum T4 was observed for the three groups studied whereas there was little change in the concentrations of plasma T3.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1996

Oleic acid-induced mitogenic signaling in vascular smooth muscle cells. A role for protein kinase C.

As an initial step in testing the hypothesis that high oleic acid concentrations contribute to vascular remodeling in obese hypertensive patients by activating protein kinase C (PKC), the effects of oleic acid on primary cultures of rat aortic smooth muscle cells (RASMCs) were studied. Oleic acid, an 18-carbon cis-monounsaturated fatty acid (18:1 [cis]), from 25 to 200 mumol/L significantly increased [3H]thymidine uptake in RASMCs with an EC50 of 41.0 mumol/L and a maximal response of 196 +/- 15% of control (P < .01). Oleic acid from 25 to 200 mumol/L caused a concentration-dependent increase in the number of RASMCs in culture at 6 days, reaching a maximum of 210 +/- 13% of control at 100 mumol/L (P < .001). PKC inhibition with 4 mumol/L bisindolyImaleimide I and PKC depletion (alpha, mu, iota, and zeta) with 24-hour exposure to 200 nmol/L phorbol 12-myristate 13-acetate in RASMCs eliminated the mitogenic effects of oleic acid but did not reduce responses to 10% FBS. Stimulation of intact cells with oleic acid induced a peak increase of cytosolic PKC activity, reaching 328 +/- 8% of control (P < .001), but did not enhance PKC activity in the membrane fraction (105 +/- 4%, P = NS). The oleic acid-induced increase of PKC activity in cell lysates was similar in the presence and absence of Ca2+, phosphatidylserine, and diolein (maximum response, 360 +/- 4% versus 342 +/- 9% of control, P = NS). Unlike phorbol 12-myristate 13-acetate, oleic acid over 24 hours did not downregulate any of the four PKC isoforms detected in RASMCs. Oleic acid treatment activated mitogen-activated protein (MAP) kinase. PKC depletion in RASMCs eliminated the rise in thymidine uptake, activation of PKC, and activation of MAP kinase in response to oleic acid. In contrast to oleic acid, 50 to 200 mumol/L stearic (18:0) and elaidic (18:1 [trans]) acids, which are less effective activators of PKC than oleic acid, did not enhance thymidine uptake. These data suggest that oleic acid induces proliferation of RASMCs by activating PKC, particularly one or more of the Ca(2+)-independent isoforms, and raise the possibility that the higher oleic acid concentrations observed in obese hypertensive patients may contribute to vascular remodeling.

Animals↗
PubMed2006

An ARC/Mediator subunit required for SREBP control of cholesterol and lipid homeostasis.

The sterol regulatory element binding protein (SREBP) family of transcription activators are critical regulators of cholesterol and fatty acid homeostasis. We previously demonstrated that human SREBPs bind the CREB-binding protein (CBP)/p300 acetyltransferase KIX domain and recruit activator-recruited co-factor (ARC)/Mediator co-activator complexes through unknown mechanisms. Here we show that SREBPs use the evolutionarily conserved ARC105 (also called MED15) subunit to activate target genes. Structural analysis of the SREBP-binding domain in ARC105 by NMR revealed a three-helix bundle with marked similarity to the CBP/p300 KIX domain. In contrast to SREBPs, the CREB and c-Myb activators do not bind the ARC105 KIX domain, although they interact with the CBP KIX domain, revealing a surprising specificity among structurally related activator-binding domains. The Caenorhabditis elegans SREBP homologue SBP-1 promotes fatty acid homeostasis by regulating the expression of lipogenic enzymes. We found that, like SBP-1, the C. elegans ARC105 homologue MDT-15 is required for fatty acid homeostasis, and show that both SBP-1 and MDT-15 control transcription of genes governing desaturation of stearic acid to oleic acid. Notably, dietary addition of oleic acid significantly rescued various defects of nematodes targeted with RNA interference against sbp-1 and mdt-15, including impaired intestinal fat storage, infertility, decreased size and slow locomotion, suggesting that regulation of oleic acid levels represents a physiologically critical function of SBP-1 and MDT-15. Taken together, our findings demonstrate that ARC105 is a key effector of SREBP-dependent gene regulation and control of lipid homeostasis in metazoans.

Amino Acid Sequence↗
PubMed1994

Regulation of fibrinolysis by non-esterified fatty acids.

The ability of oleic acid to modulate fibrinolysis was measured by following the urokinase-mediated and plasminogen-dependent cleavage of 125I-labelled fibrin clots. Oleic acid levels within the physiological range exerted a concentration-dependent inhibition of urokinase-mediated fibrinolytic activity. SDS/PAGE revealed that oleic acid enhances urokinase activity but simultaneously increases the autolytic cleavage of the newly formed low-molecular-mass subunit of plasmin. Oleic acid-induced cleavage of this subunit containing the catalytic site of plasmin was suppressed by the plasmin substrate H-D-valyl-L-leucyl-L-lysine-p-nitroanilide (S-2251) and was prevented by alpha 2-antiplasmin. A concentration-dependent inhibition of the activity of purified plasmin on 125I-labelled fibrin clot was also observed; 93% and 50% inhibition was noted with 150 microM and 32 microM oleic acid respectively. Oleic acid at 200 microM also effectively displaced plasmin prebound to a polylysine-Sepharose column. Examination of the fatty acid specificity showed that a minimal chain length of 16 carbon atoms and the presence of at least one double bond, preferably in a cis configuration, were required for inhibition of the fibrinolytic activity of plasmin. Oleic acid at a concentration that produced only a minimal inhibition of plasmin activity induced a marked inhibition by palmitic acid, while palmitic acid alone is ineffective. The findings suggest that oleic acid stimulates plasminogen activation and modulates the fibrinolytic and autolytic activities of plasmin.

Amino Acid Sequence↗
PubMed1996

Unesterified long chain fatty acids inhibit the binding of single chain urokinase to the urokinase receptor.

The interaction of single chain urokinase with its receptor accelerates plasminogen activator activity on cell surfaces and induces intracellular signalling in several cell types. To date, no physiologic inhibitor of this binding has been identified. We report that the binding of scuPA to its cellular receptor is inhibited by long chain fatty acids such as oleic acid (C18, delta 9) at physiological plasma concentrations. Inhibition of single chain urokinase binding to human trophoblastic cells by long chain fatty acids was dose-dependent and saturable. Fifty percent of the binding was inhibited at an oleic acid concentration of 27 microM, while inhibition was maximal (75%) at 150 microM oleic acid. The inhibitory potency of oleic acid was unaffected by fatty acid free albumin or human plasma. Inhibition of single chain urokinase binding by free fatty acid analogues was critically dependent on chain length (> C14 required for inhibition) and was proportional to the extent of unsaturation. Only the fraction of specific scuPA binding to trophoblasts that was dependent on uPAR was susceptible to inhibition by oleic acid, while binding of scuPA to vitronectin, thombospondin, and the alpha 2-macroglobulin receptor/low-density lipoprotein-related receptor was not. [3H]Oleic acid bound specifically to recombinant soluble uPAR in a 1:1 molar ratio in the presence or absence of plasma and totally blocked its specific binding to a cell line expressing glycosyl phosphatidylinositol-linked single chain urokinase. These results indicate that oleic acid and other unsaturated long chain free fatty acids may serve as physiologic regulators of proteolytic events and intracellular signalling that depend upon the interaction of urokinase with its receptor.

Animals↗
PubMed1991

Interaction of LY171883 and other peroxisome proliferators with fatty-acid-binding protein isolated from rat liver.

Fatty-acid-binding protein (FABP) is a 14 kDa protein found in hepatic cytosol which binds and transports fatty acids and other hydrophobic ligands throughout the cell. The purpose of this investigation was to determine whether LY171883, a leukotriene D4 antagonist, and other peroxisome proliferators bind to FABP and displace an endogenous fatty acid. [3H]Oleic acid was used to monitor the elution of FABP during chromatographic purification. [14C]LY171883 had a similar elution profile when substituted in the purification, indicating a common interaction with FABP. LY171883 and its structural analogue, LY189585, as well as the hypolipidaemic peroxisome proliferators clofibric acid, ciprofibrate, bezafibrate and WY14,643, displaced [3H]oleic acid binding to FABP. Analogues of LY171883 that do not induce peroxisome proliferation only weakly displaced oleate binding. [3H]Ly171883 bound directly to FABP with a Kd of 10.8 microM, compared with a Kd of 0.96 microM for [3H]oleate. LY171883 binding was inhibited by LY189585, clofibric acid, ciprofibrate and bezafibrate. These findings demonstrate that peroxisome proliferators, presumably due to their structural similarity to fatty acids, are able to bind to FABP and displace an endogenous ligand from its binding site. Interaction of peroxisome proliferators with FABP may be involved in perturbations of fatty acid metabolism caused by these agents as well as in the development of the pleiotropic response of peroxisome proliferation.

Acetophenones↗