SEARCH · Search PubMed

Results for “PALMITIC 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.

SourceResearch connectionFrom yearThrough year

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

At least 1,009 records · Page 56Linked to original sources

PubMed2006

Glucose, palmitate and pro-inflammatory cytokines modulate production and activity of a phagocyte-like NADPH oxidase in rat pancreatic islets and a clonal beta cell line.

AIMS/HYPOTHESIS: Acute or chronic exposure of beta cells to glucose, palmitic acid or pro-inflammatory cytokines will result in increased production of the p47(phox) component of the NADPH oxidase and subsequent production of reactive oxygen species (ROS). METHODS: Rat pancreatic islets or clonal rat BRIN BD11 beta cells were incubated in the presence of glucose, palmitic acid or pro-inflammatory cytokines for periods between 1 and 24 h. p47(phox) production was determined by western blotting. ROS production was determined by spectrophotometric nitroblue tetrazolium or fluorescence-based hydroethidine assays. RESULTS: Incubation for 24 h in 0.1 mmol/l palmitic acid or a pro-inflammatory cytokine cocktail increased p47(phox) protein production by 1.5-fold or by 1.75-fold, respectively, in the BRIN BD11 beta cell line. In the presence of 16.7 mmol/l glucose protein production of p47(phox) was increased by 1.7-fold in isolated rat islets after 1 h, while in the presence of 0.1 mmol/l palmitic acid or 5 ng/ml IL-1beta it was increased by 1.4-fold or 1.8-fold, respectively. However, palmitic acid or IL-1beta-dependent production was reduced after 24 h. Islet ROS production was significantly increased after incubation in elevated glucose for 1 h and was completely abolished by addition of diphenylene iodonium, an inhibitor of NADPH oxidase or by the oligonucleotide anti-p47(phox). Addition of 0.1 mmol/l palmitic acid or 5 ng/ml IL-1beta plus 5.6 mmol/l glucose also resulted in a significant increase in islet ROS production after 1 h, which was partially attenuated by diphenylene iodonium or the protein kinase C inhibitor GF109203X. However, ROS production was reduced after 24 h incubation. CONCLUSIONS/INTERPRETATION: NADPH oxidase may play a key role in normal beta cell physiology, but under specific conditions may also contribute to beta cell demise.

Animals↗

PubMed1973

The irreversible disposal rate of free fatty acids in the plasma of fed and starved rats.

1. The irreversible disposal rate coefficient for free fatty acids in the plasma of fed and starved rats was determined after a single intravenous injection of [1-(14)C]palmitic acid into each rat. The dose of labelled palmitic acid was given as a complex with (131)I-labelled albumin in rat serum. The total amount of [1-(14)C]palmitic acid remaining in the plasma was determined at short times after injection from the (14)C/(131)I ratio in the injected serum and in the collected plasma. The rate coefficient was determined from the area under the curve that describes the disappearance of [1-(14)C]palmitic acid with time from the plasma. Possible sources of error in these determinations are discussed. 2. The irreversible disposal rate coefficient was significantly higher in fed rats (2.07min(-1)) than in rats which had been starved for 24h (1.53min(-1)). The possible relationship between this difference and the processes whereby free fatty acids are removed from the plasma is discussed briefly. 3. An estimate of the irreversible disposal rate for free fatty acids in plasma was made from the concentration of free fatty acids in plasma and from the volume of distribution of (131)I-labelled albumin. The irreversible disposal rate was significantly lower in the fed state than in the starved.

Animals↗

PubMed1984

Plasma protein binding and interaction studies with piroxicam.

The binding of non-steroidal antirheumatic drug piroxicam to human serum albumin, human plasma and serum has been studied by equilibrium dialysis at 22 degrees C, pH 7.4. The binding data were analyzed according to Scatchard model. The values of binding parameters obtained for human serum albumin are quite similar to those obtained for human plasma and serum (N1 = 0.3, K1 = 3.0 x 10(5) l/mol; N2 = 7, K2 = 3.5 x 10(3) l/mol). We suggest that piroxicam interacts with the albumin fraction in human plasma proteins. The displacement of piroxicam (in the therapeutical concentration of 4.5 x 10(5) mol/l) from the binding to human serum albumin and human plasma has been studied. The concentration of albumin and albumin fraction in plasma was 2.9 x 10(-4) mol/l. The displacement substances were drugs--diazepam, warfarin and salicylic acid, and endogenous substances-bilirubin and palmitic acid. Only in the presence of salicylic acid in high clinical concentration (14.5 x 10(-4) mol/l) and palmitic acid in the molar ratio to albumin 5:1, free piroxicam substantially increased, which may be of clinical significance. Other studied substances displaced piroxicam only in high concentrations exceeding the therapeutical and physiological range. The evidence was found for the similarity of piroxicam and warfarin high-affinity binding site.

Anti-Inflammatory Agents↗

PubMed1991

Leukotriene B4 promotes phospholipid acylation in human neutrophils.

The present study was undertaken to test the hypothesis that leukotriene B4 (LTB4) may promote extracellular fatty acid incorporation into neutrophil choline glycerophospholipids (PC) to replenish phospholipids after deacylation. Incubation of human neutrophils with LTB4 (1.5 to 150 nM) for 1 to 5 min resulted in increased fatty acid incorporation into phosphatidylinositol (PI), diacyl-sn-glycero-3-phosphocholine (diacyl-GPC) and alkylacyl-GPC. The magnitude of stimulation (percentage of control) of fatty acid incorporation appears to reflect increased activity of the acyltransferase catalyzing acylation of the respective lysophospholipids. LTB4 stimulation of arachidonic acid incorporation into PI was greater than into PC, whereas the stimulation of palmitic acid incorporation into PC was greater than into PI. LTB4 stimulated phosphatidic acid labeling by palmitic acid but not by arachidonic acid. LTB4 and 1-O-alkyl-2-N-methylcarbamyl-sn-glycero-3-phosphocholine (cPAF) exhibited a similar stimulatory effect on fatty acid incorporation into the PC fraction. Phosphate analysis could not detect changes in the mass of PI or of PC in neutrophils exposed to LTB4 or cPAF. The results suggest that increased fatty acid incorporation into phospholipids in LTB4-activated neutrophils reflects activation of phospholipase A2 and acyltransferases as well as of de novo phospholipid synthesis.

Acylation↗

PubMed1977

Intestinal absorption of palmitate and 2-aminoisobutyric acid in piglets infected with Strongyloides ransomi.

Piglets were infected with 5000 or 15,000 third stage larvae of Strongyloides ransomi/kg of body weight. On the 15th day post infection absorption of the amino acid 14C alpha-amino-isobutyric acid (AIB) and the fatty acid 3H palmitic acid were studied. It was found that the onset of absorption of amino and fatty acids was delayed in the infected animals. Defective absorption of the amino acid was found in heavily infected piglets, whereas in moderate infection there was no failure of absorption from the entire small intestine. There was no difference in the rates of absorption of 3H-palmitic acid between infected and control piglets.

Aminoisobutyric Acids↗

PubMed1984

Mechanisms of fatty acid effects on sarcoplasmic reticulum. III. The effects of palmitic and oleic acids on sarcoplasmic reticulum function--a model for fatty acid membrane interactions.

The mechanism by which palmitic and oleic acids modify calcium sequestration by sarcoplasmic reticulum vesicles was investigated by examining the effects of these fatty acids on calcium-dependent ATPase activity, on the phosphoenzyme intermediates found during calcium sequestration reactions, and on passive membrane permeability to calcium. The calcium sequestered in the presence of these fatty acids was also characterized by determining the amount exchangeable with the extravesicular pool or released by the ionophore A23187. In the presence of 50 microM ATP, 18 microM palmitic acid enhanced and 18 microM oleic acid inhibited calcium sequestration, whereas both fatty acids stimulated ATPase activity. Neither fatty acid had significant effects on the amount or distribution of the phosphoenzyme formed during the calcium transport reaction. Palmitic acid stimulated calcium sequestration only when ATP was present. Oleic acid caused the release of a portion of the accumulated calcium during ATP-supported calcium sequestration and also enhanced the release observed in ATP-depleted reactions. A portion of the calcium sequestered in the presence of palmitic acid appears to be incorporated into a nonexchangeable and ionophore-insensitive calcium pool, although the latter was estimated to be considerably larger than the nonexchangeable pool. These data support the hypothesis that oleic acid inhibits calcium sequestration by increasing membrane permeability to calcium, whereas palmitic acid appears to stimulate calcium sequestration by interacting with a portion of the calcium within the vesicles to form a separate, poorly exchangeable calcium pool.

Adenosine Triphosphate↗

PubMed1986

Output of triglyceride from the sebaceous gland and to the skin surface of cattle.

Radiolabelled fatty acids, when injected intradermally into cattle skin, were largely incorporated into the triglyceride and phospholipid fractions of the sebaceous gland lipids. Linoleic acid was incorporated into the triglycerides to a greater extent than oleic or palmitic acids, whereas the phospholipids had a greater affinity for palmitic acid. The peak uptake of linoleic acid into the glandular triglyceride fraction was at about 61 hours compared with 52 hours and three hours for oleic and palmitic acids. Radioactively 14C labelled triglycerides appeared on the skin surface within one day of intradermal injection of 14C linoleic acid. At an ambient temperature of 20 degrees C, a single output-peak occurred at nine days while at 35 degrees C two peaks at four and eight to nine days were observed. From the data an estimate of 6.5 days for the mean storage time of sebum triglycerides in the hair follicle canal at 20 degrees C has been made.

Animals↗

PubMed1977

Effect of acute hypobaric hypoxia on fatty acid metabolism in rat lung.

Exposure of male albino rats in the weight range of 70-200 g to 25,000 ft of simulated altitude for 6 h at 32 degrees C caused an increase in plasma free fatty acids with decreased oxidation of palmitic acid-1-14C in lung slices of hypoxic rats. The in vivo esterification of palmitic acid-1-14C to form truglycerides, phosphatidylcholine and phosphatidylethanolamine was also low indicating decreased utilization of fatty acids by hypoxic lungs. De novo lipogenesis was observed to decreased to decrease because of decreased fatty acid biosynthesis as judged from acetate---14C incorporation. The specific activities of triglycerides, phosphatidylcholine and free cholesterol were also decreased. The decreased incorporation into phosphatidylcholine affected the incorporation into phosphatidylcholine of alveolar surfactant (2,000 g sediment fraction). The results are discussed in view of possible decreased energy status of hypoxic lungs.

Animals↗

PubMedDate not supplied

Determination of the route of medium-chain and long-chain fatty acid absorption by direct measurement in the rat.

BACKGROUND: Medium-chain triglycerides are used for the treatment of malabsorptive states. We measured directly the absorption of medium- and long-chain fatty acids via the mesenteric lymphatics and portal vein in normal animals. These results may be useful in guiding therapy for short-bowel syndrome. METHODS: Under anesthesia, male Lewis rats (n = 6) underwent placement of jugular and portal venous lines, mesenteric lymphatic duct cannula, and a duodenal tube. After recovery, a 0.3% lauric acid (C12:0) and 0.37% palmitic acid (C16:0) solution solublized with 3.25 mmol/L lecithin and 23.75 mmol/L taurocholic acid in phosphate-buffered saline was infused at a rate of 3 mL/h via the duodenal tube. After stabilization of lymphatic flow (6 hours), a pulse of radiolabeled lauric and palmitic acid was given via the duodenal tube; absorption was measured by collection of lymphatic fluid and sampling of the portal and jugular venous blood for 4 hours. RESULTS: The amount of acid recovered in the lymphatics was 51% +/- 6% (mean +/- SD) for lauric and 59% +/- 6% for palmitic. For both fatty acids, < 1% in total was recovered from the portal vein during the 4-hour postbolus period; thereafter, levels in the blood were constant and very low. At necropsy, the majority of the remaining label was found in the intestine. CONCLUSIONS: These results show no evidence for the preferential absorption of medium-chain fatty acids directly via the portal vein in this model. We suggest that further studies be done to measure directly portal vein absorption of the medium-chain fatty acids.

Absorption↗

PubMed1987

Does carnitine have a role in fat absorption?

The effect of D-carnitine and tetradecylglycidic acid (TDGA), an inhibitor of carnitine palmitoyltransferase, on intestinal absorption of palmitic acid was determined. The proximal intestinal segment was ligated in adult male rats and filled with 0.5 microCi of 14C-palmitic acid alone or with either D-carnitine or TDGA. Thirty minutes later the radioactivity was determined in the intestinal lumen, intestinal wall and plasma. The absorption of palmitic acid was decreased in the presence of D-carnitine (10 mg/ml) as evidenced by significantly lower levels of radioactivity in the gut wall and the plasma and by significantly greater residual radioactivity in the lumenal contents. L-carnitine had no effect on plasma radioactivity but if D- and L-carnitine were given together the effect of D-carnitine was still in evidence. TDGA also inhibited intestinal absorption of palmitic acid.

Animals↗

PubMed1984

Cell-free fatty acid acylation of Semliki Forest viral polypeptides with microsomal membranes from eukaryotic cells.

Using [14C]palmitoyl-CoA as donor and deacylated (fatty acid-free) structural proteins of Semliki Forest virus as exogenous acceptors, palmitic acid was incorporated into polypeptide in a cell-free system with microsomes of baby hamster kidney cells, chicken embryo fibroblasts, and rat liver cells. Out of the four viral proteins (E1, E2, E3, and C) only E1 becomes acylated enzymatically. The protein bound fatty acids of the in vitro product are resistant to detergents and to organic extractions but can be released with hydroxylamine thus affording the typical features of acyl-proteins. Fatty acid transfer to E1 requires the presence of microsomes and is abolished when microsomal membranes are omitted or boiled prior to the incubation. Exogenous acceptor protein E1 had to be deacylated prior to the incubation in order to function during acylation in vitro since no fatty acid chains were transferred into untreated viral E1. Acylation of E1 is time- and temperature-dependent and can be stimulated by increasing the concentrations of acceptor protein, microsomal membranes, or of exogenous fatty acid donor. While Mg2+ does not influence the transfer reaction, Mn2+ leads to a dose-dependent inhibition commencing at a concentration of 1 mM. The cell-free acylation activity fails to show high specificity with regard to the chain length or degree of saturation of the acyl chain used as lipid substrate since palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), and myristic acid (C14:0) are all transferred onto E1 as long as ATP is present in the incubation mixture. The type of detergent and its concentration were found to be critical for this acylation in vitro. Nonidet P-40 or Triton X-100 both up to a 0.2% concentration allowed the reaction while no enzymatic transfer of palmitic acid onto E1 was detected in the presence of octyl-beta-D-glucoside and Tween 20 at the conditions used for the in vitro incubation. However, when acyl transfer onto lipid acceptors was monitored, the incorporation of fatty acids into the neutral- and phospholipids functioned normally in octyl-beta-D-glucoside only, while Nonidet P-40 and Triton X-100 inhibited the acylation of all neutral lipids and of most of the phospholipids completely.(ABSTRACT TRUNCATED AT 400 WORDS)

Acylation↗

PubMed1979

An in vivo comparison of acetate and palmitate as precursors of surfactant phosphatidylcholine.

3-Day-old rabbits were injected simultaneously with [(3)H]acetate and [(14)C]-palmitic acid. The specific activities of lung, lamellar body and surfactant phosphatidylcholine and disaturated phosphatidylcholine were measured at time intervals from 10 min to 23 h following isotope administration. Palmitic acid contained 87% of the acetate radioactivity recovered from lung and surfactant phosphatidylcholine. The relative specific activities of surfactant phosphatidylcholine and disturated phosphatidylcholine labeled with acetate were 2.02 and 1.86 times those measured using the palmitic acid label. Apparently the palmitic acid synthesized from acetate is preferentially incorporated into lung phosphatidylcholines and disaturated phosphatidylcholines which are destined to become surfactant.

Acetates↗

PubMed1975

Bovine serum albumin. Study of the fatty acid and steroid binding sites using spin-labeled lipids.

Three spin-labeled derivatives of stearic acid and two derivatives of palmitic acid have been used to study the structure of the strong fatty acid binding site of bovine serum albumin. The steroid and indole binding sites have been studied using spin-labeled derivatives of androstol and indole, respectively. Paramagnetic resonance and fluorescence quenching data suggest that the fatty acid, steroid, and indole binding sites may be identical. The mobility of the nitroxyl group at C-8 of palmitic acid bound to albumin at a 1:1 molar ratio is unaffected when the carboxyl group is esterified. When the nitroxyl group is located at C-5 on this acid its motion is detectably increased by esterification of the carboxyl group but the magnitude of this change is small. This result suggests that the carboxyl group may play a minor role in the binding of fatty acids to the strongest fatty acid binding site of albumin. When stearic acid derivatives bearing the nitroxide at C-5, C-12, and C-16 are bound to albumin at a ligand to albumin ratio of 1, the order of mobility at 0-30 degrees is C-16 greater than C-12 congruent to C-5. Although motion at the methyl terminus is always greater than at the COOH terminus in the range 0-60 degrees, a simple monotonic increase in chain motion between the two termini is not observed. Arrhenius plots of the motion parameters for these bound fatty acids show two abrupt changes in slope. The temperature ranges for these changes are 15-23 degrees and 38-45 degrees. These results suggest that when one mole of spin-labeled fatty acid is bound to albumin, the protein undergoes a conformational change in each of these temperature ranges.

Animals↗

PubMed2004

Reduced lipid oxidation in skeletal muscle from type 2 diabetic subjects may be of genetic origin: evidence from cultured myotubes.

Insulin resistance in skeletal muscle in vivo is associated with reduced lipid oxidation and lipid accumulation. It is still uncertain whether changes in lipid metabolism represent an adaptive compensation at the cellular level or a direct expression of a genetic trait. Studies of palmitate metabolism in human myotubes established from control and type 2 diabetic subjects may solve this problem, as genetic defects are preserved and expressed in vitro. In this study, total uptake of palmitic acid was similar in myotubes established from both control and type 2 diabetic subjects under basal conditions and acute insulin stimulation. Myotubes established from diabetic subjects expressed a primary reduced palmitic acid oxidation to carbon dioxide with a concomitantly increased esterification of palmitic acid into phospholipids compared with control myotubes under basal conditions. Triacylglycerol (TAG) content and the incorporation of palmitic acid into diacylglycerol (DAG) and TAG at basal conditions did not vary between the groups. Acute insulin treatment significantly increased palmitate uptake and incorporation of palmitic acid into DAG and TAG in myotubes established from both study groups, but no difference was found in myotubes established from control and diabetic subjects. These results indicate that the reduced lipid oxidation in diabetic skeletal muscle in vivo may be of genetic origin; it also appears that TAG metabolism is not primarily affected in diabetic muscles under basal physiological conditions.

Blood Glucose↗

PubMed1999

Stabilization of rat serum proteins following oral administration of fish oil.

The mechanism of action of fish oil (FO), currently used in different chronic inflammatory conditions such as rheumatoid arthritis (RA), is not completely understood, although it is thought that it could alter the metabolism of endogenous autacoids. In addition, we hypothesized that the known capability of fatty acids (FA) of stabilizing serum albumin and perhaps other proteins, may be of pharmacological relevance considering that it is shared by other anti-rheumatic agents (e.g. nonsteroidal antiinflammatory drugs). Thus, we studied the effect of oral administration of FO and corn oil (CO), a vegetable oil with a different composition, on the stability of rat serum proteins, evaluated by a classical in vitro method based on heat-induced protein denaturation. FO, and, to a lower extent, CO inhibited heat-induced denaturation of rat serum (RS): based on the inhibitory activity (EC50) of the major fatty acids against heat-induced denaturation of RS in vitro, it was possible to speculate that in vivo effects of palmitic acid (C16:0) and eicosapentaenoic acid (EPA, C20:5, n-3) may be more relevant than that of linolenic acid (C18:2). To better investigate this phenomenon, we extracted albumin from the serum of animals treated or not with FO with a one-step affinity chromatography technique, obtaining high purity rat serum albumin preparations (RSA-CTRL and RSA-FO), as judged by SDS-PAGE with Coomassie blue staining. When these RSA preparations were heated at 70 degrees C for 30 min, it was noted that RSA-FO was much more stable than RSA-CTRL, presumably due to higher number of long chain fatty acids (FA) such as palmitic acid or EPA. In conclusion, we provided evidences that oral administration of FO in the rat stabilizes serum albumin, due to an increase in the number of protein bound long chain fatty acids (e.g. palmitic acid and EPA). We speculate that the stabilization of serum albumin and perhaps other proteins could prevent changes of antigenicity due to protein denaturation and glycosylation, which may trigger pathological autoimmune responses, suggesting that this action may be involved in the mode of action of FO in RA and other chronic inflammatory diseases.

Administration, Oral↗

PubMed1977

Adjuvant activities of chemically modified water-soluble substances from Mycobacterium tuberculosis.

Water-soluble peptidoglycan fragments extracted from the cells of two strains of Mycobacterium tuberculosis var. hominis were chemically conjugated with lauric or with palmitic acid. The coupling reaction was confirmed by physicochemical procedures. The native and the fatty acid-conjugated substances were studied for their adjuvant activity in the induction of delayed type hypersensitivity (DTH) reactions in guinea-pigs and on the production of circulating antibodies in the rabbit. Palmitic acid conjugation of one of the substances increased its adjuvanticity on DTH in the presence of mineral oil; lauric or palmitic acid conjugation rendered the substances adjuvant-active on DTH in the absence of mineral oil. Lauric acid, but not palmitic acid conjugation conferred on both substances an adjuvant activity on antibody production in the absence of mineral oil. Furthermore, lauric acid conjugation of one of the substances led to the appearance of an in vitro mitogen-like activity for murine spleen lymphocytes. In conclusion, fatty acid conjugation exerted a significant modifying effect on the immuno-potentiating activities of these peptidoglycan fragments, and such a chemical procedure may lead to the development of substances exerting a full adjuvant activity without the need of injecting them in an oily vehicle.

Adjuvants, Immunologic↗

PubMed1993

Formation of fatty acid propyl esters in liver, lung and pancreas of rats administered 1-propanol.

The esterification of fatty acids by ethanol has been associated with a number of adverse reactions. In this study, the administration of 1-propanol (3 ml/kg 24 and 12 hours prior to measurements) to rats resulted in the formation of fatty acid propyl esters of oleic acid, lauric acid and to a lesser extent, palmitic acid and myristic acid. Formation was highest in liver and pancreas and was lower in lung.

1-Propanol↗

PubMed1989

Modulation of prostaglandin E2 catabolism and action by fuel substrates in rat hepatocytes.

The hepatic level of prostaglandins will reflect the balance between synthesis of prostaglandins and their rapid catabolism via beta-oxidation by hepatocytes. In the present study we examined the effect of physiological fuel substrates on the breakdown and action of prostaglandin E2 (PGE2) in isolated rat hepatocytes. Palmitic acid (0.32 mM), a long-chain fatty acid, inhibited the rate of PGE2 breakdown (10(-7) M) by approx. 80%. As the palmitic acid concentration was increased from 0 to 0.8 mM, the percentage of PGE2 remaining in the incubation 5 min following prostaglandin addition was raised from approx. 10% to over 98%. Octanoic acid (0.8 mM) also inhibited PGE2 catabolism, while butyric acid (0.8 mM) and pyruvic acid (2.5 mM) were without effect. The inhibition of glucagon-stimulated glycogenolysis by PGE2 was increased in the presence of 0.6 mM palmitic acid, consistent with decreased PGE2 catabolism. These studies demonstrate that changes within the range of free fatty acid concentrations seen physiologically in vivo may dramatically alter PGE2 catabolism and, therefore, the effect of PGE2 to modulate hormonal action in the liver.

Animals↗