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PubMed1985

Retention and clearance of C-11 palmitic acid in ischemic and reperfused canine myocardium.

Free fatty acids are the major energy source for cardiac muscle. Oxidation of fatty acid decreases or even ceases during ischemia. Its recovery after transient ischemia remains largely unexplored. Using intracoronary carbon-11 palmitic acid as a tracer of myocardial fatty acid metabolism in an open chest dog model, retention and clearance of tracer in myocardium were evaluated at control, during ischemia and after reperfusion following a 20 minute occlusion of the left anterior descending coronary artery. Myocardial C-11 time-activity curves were analyzed with biexponential curve-fitting routines yielding fractional distribution and clearance half-times of C-11 palmitic acid in myocardial tissue. In animals with permanent occlusion and intracoronary injection of C-11 palmitic acid distal to the occlusion site, the relative size and half-time of the early clearance curve component differed markedly from control values and did not change with ongoing ischemia. Conversely, in animals with only 20 minutes of coronary occlusion, the relative size of the early C-11 clearance phase was still significantly depressed at 20 and 90 minutes of reperfusion but returned to control level at 180 minutes. Tissue C-11 clearance half-times remained significantly prolonged throughout the reperfusion period. Regional function in reperfused myocardium monitored with ultrasonic crystals recovered slowly and was still less than control after 3 hours of reperfusion. The data indicate that after transient ischemia, myocardial fatty acid metabolism fails to recover immediately. Because the metabolic recovery occurs in parallel with recovery of regional function, C-11 palmitic acid in conjunction with positron tomography may be useful for studying regional fatty acid metabolism noninvasively after an ischemic injury, and may be helpful in identifying reversible tissue injury.

Animals↗
PubMedDate not supplied

Antitumor activity of palmitic acid found as a selective cytotoxic substance in a marine red alga.

In a previous report, we discussed an extract from a marine red alga, Amphiroa zonata, which shows selective cytotoxic activity to human leukemic cells, but no cytotoxicity to normal human dermal fibroblast (HDF) cells in vitro. In this study, we identified palmitic acid, a selective cytotoxic substance from the marine algal extract, and investigated its biological activities. At concentrations ranging from 12.5 to 50 micrograms/ml, palmitic acid shows selective cytotoxicity to human leukemic cells, but no cytotoxicity to normal HDF cells. Furthermore, palmitic acid induces apoptosis in the human leukemic cell line MOLT-4 at 50 micrograms/ml. Palmitic acid also shows in vivo antitumor activity in mice. One molecular target of palmitic acid in tumor cells is DNA topoisomerase I, however, interestingly, it does not affect DNA topoisomerase II, suggesting that palmitic acid may be a lead compound of anticancer drugs.

Animals↗
PubMedDate not supplied

Absorbability of oleic and palmitic acid in young chicks. Effect of yolk sac ablation.

The aims of the present study were: 1) to describe the changes in the absorption of free oleic and palmitic acids in young chicks during the first two weeks after hatching; 2) to find out if yolk sac ablation induces any change in the absorbability of such fatty acids. The study was carried out in normal and yolk-sac-ablated broiler chicks aged 2, 8 and 13 days. 14C-labelled oleic and palmitic acids were given p.o. in suspension. Stools were collected for 48h and the recovery of radioactivity was determined and considered as an indicator of the extent of absorption. Our results indicate that the absorption of palmitic acid decreased with age (p less than 0.05) whereas the absorption of oleic acid increased significantly (p less than 0.005). The changes in the absorptive capacity for each fatty acid occurred during the first week. The absorption of both fatty acids was greater in yolk-sac-ablated chicks (p less than 0.05). The relative contents of different fatty acids in yolk lipids was investigated. The results clearly indicate that the ratio OA/PA linearly increased from hatching until the 4th day. Thus the possibility that yolk sac lipids passing to the intestine through the yolk stalk are able to modify the absorptive processes cannot be excluded.

Aging↗
PubMed1994

Evidence that palmitic acid is absorbed as sn-2 monoacylglycerol from human milk by breast-fed infants.

Milk fatty acids consist of about 20-25% palmitic acid (16:0), with about 70% of 16:0 esterified to the sn-2 position of the milk triacylglycerols. Hydrolysis of dietary triacylglycerols by endogeneous lipases produces sn-2 monoacylglycerols and free fatty acids, which are absorbed, reesterified, and then secreted into plasma. Unesterified 16:0 is not well absorbed and readily forms soaps with calcium in the intestine. The positioning of 16:0 at the sn-2 position of milk triacylglycerols could explain the high coefficient of absorption of milk fat. However, the milk lipase, bile salt-stimulated lipase, has been suggested to complete the hydrolysis of milk fat to free fatty acids and glycerol. These studies determined whether 16:0 is absorbed from human milk as sn-2 monopalmitin by comparison of the plasma triacylglycerol total and sn-2 position fatty acid composition between breast-fed and formula-fed term gestation infants. The human milk and formula had 21.0 and 22.3% of 16:0, respectively, with 54.2 and 4.8% 16:0 in the fatty acids esterified to the 2 position. The plasma triacylglycerol total fatty acids had 26.0 +/- 0.6 and 26.2 +/- 0.6% of 16:0, and the sn-2 position fatty acids had 23.3 +/- 3.3 and 7.4 +/- 0.7% of 16:0 in the three-month-old exclusively breast-fed (n = 17) and formula-fed (n = 18) infants, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Feeding↗
PubMed1994

Fat high in stearic acid favorably affects blood lipids and factor VII coagulant activity in comparison with fats high in palmitic acid or high in myristic and lauric acids.

The effect of fats high in individual, prevalent saturated dietary fatty acids on lipoproteins and hemostatic variables in young healthy subjects was evaluated in a randomized strictly controlled metabolic feeding study. Three experimental diets: shea butter (S; 42% stearic acid), palm oil (P; 43% palmitic palmitic acid), and palm-kernel oil with high-oleic sunflower oil (ML; 10% myristic acid, 30% lauric acid) were served to 15 men for 3 wk each, separated by washout periods. Diet S compared with diet P resulted in significant reduction in plasma cholesterol (22%) LDL cholesterol (26%), apolipoprotein B (18%), HDL cholesterol (12%), apolipoprotein A-I (13%), and a 13% lower factor VII coagulant activity (P = 0.001). Similar differences were observed between diets S and ML. In conclusion, intake of shea butter high in stearic acid favorably affects blood lipids and factor VII coagulant activity in young men, compared with fats high in saturated fatty acids with 12-16 carbons.

Adult↗
PubMed1999

P450BM-3: absolute configuration of the primary metabolites of palmitic acid.

P450BM-3, a catalytically self-sufficient, soluble bacterial P450, contains on the same polypeptide a heme domain and a reductase domain. P450BM-3 catalyzes the oxidation of short- and long-chain, saturated and unsaturated fatty acids. The three-dimensional structure of the heme domain both in the absence and in the presence of fatty acid substrates has been determined; however, the fatty acid in the substrate-bound form is not adequately close to the heme iron to permit a prediction regarding the stereoselectivity of oxidation. In the case of long-chain fatty acids, the products can also serve as substrate and be metabolized several times. In the current study, we have determined the absolute configuration of the three primary products of palmitic acid hydroxylation (15-, 14-, and 13-OH palmitic acid). While the 15- and 14-hydroxy compounds are produced in a highly stereoselective manner (98% R, 2% S), the 13-hydroxy is a mixture of 72% R and 28% S. We have also examined the binding of these three hydroxy acids to P450BM-3 and shown that only two of them (14-OH and 13-OH palmitic acid) can bind to and be further metabolized by P450BM-3. The results indicate that in contrast to the flexibility of palmitoleic acid bound to the oxidized enzyme, palmitic acid is rigidly bound in the active site during catalytic turnover.

Arachidonic Acid↗
PubMed1998

The effect of age and gender on the metabolic disposal of [1-13C] palmitic acid.

OBJECTIVE: To examine the effect of age and gender on the metabolic disposal of [1-13C]palmitic acid. DESIGN: Cross-sectional. SETTING: Clinical Nutrition and Metabolism Unit at Southampton General Hospital, Institute of Human Nutrition, University of Southampton. SUBJECTS AND MEASUREMENTS: Twelve children (5 boys and 7 girls; aged 5-10 y) and six men (BMI 23.3 +/- 2.6 kg/m2; aged 20-30 y) were recruited. Following oral administration of a bolus dose of [1-13C]palmitic acid (10 mg/kg body weight) consumed with a test meal (1667 kJ) the excretion of 13C-label was measured on breath as 13CO2 over 24 h and in stool over 5 d to account for differences in absorption of [1-13C]palmitic acid. The 13C-enrichment of samples was determined by continuous flow-isotope ratio mass spectrometry. Net substrate oxidation was estimated from gaseous exchange measurements in the postabsorptive state and over 6 h postprandially. RESULTS: The excretion of 13CO2 on breath varied between subjects both in the pattern and amount excreted over 24 h. Breath 13CO2 was not different between boys (61.0 +/- 22.4% of absorbed dose) and girls (54.2 +/- 17.9% of absorbed dose). The excretion of breath 13CO2 was less in the men (35.1 +/- 9.3% of absorbed dose; P = 0.005) and that observed previously by our group in women (30.7 +/- 6.7% of absorbed dose; P = 0.005) than in the children. Net fat oxidation was greater in the children in both the postabsorptive (2.43 +/- 0.78 g/h) and postprandial (11.89 +/- 3.13 g/6 h) states than in the men (0.93 g/h +/- 1.50; P = 0.016; 9.86 +/- 10.53 g/6 h; NS) and women studied previously (0.53 +/- 0.68 g/h; P = 0.003; 0.03 +/- 3.21 g/6 h; P = 0.001). CONCLUSIONS: Our observations that children oxidised nearly twice the amount of [1-13C]palmitic acid than adults in conjunction with greater net fat oxidation in children than adults in both the postabsorptive and postprandial states should be considered before current UK dietary recommendations for fat and saturated fats, developed for adults, are applied to growing children. For dietary recommendations to be developed further more information is required, particularly in groups of infants and the elderly, about the factors that influence the postprandial handling of dietary fat.

Absorption↗
PubMed1997

Gastrointestinal handling of [1-13C]palmitic acid in healthy controls and patients with cystic fibrosis.

AIM: To examine the gastrointestinal handling of [1-13C]palmitic acid given as the free acid by measuring the excretion of 13C label in stool in 16 healthy children and 11 patients with cystic fibrosis on their habitual enzyme replacement treatment. METHODS: After an overnight fast, each child ingested 10 mg/kg body weight [1-13C]palmitic acid with a standardised test meal of low natural 13C abundance. A stool sample was collected before the test and all stools were collected thereafter for a period of up to five days. The total enrichment of 13C in stool and the species bearing the 13C label was measured using isotope ratio mass spectrometry. RESULTS: The proportion of administered 13C label excreted in stool was 24.0% (range 10.7-64.9%) in healthy children and only 4.4% (range 1.2-11.6%) in cystic fibrosis patients. The enrichment of 13C in stool was primarily restricted to the species consumed by the subjects (that is as palmitic acid). CONCLUSIONS: There does not appear to be a specific defect in the absorption of [1-13C]palmitic acid in patients with cystic fibrosis. The reasons why cystic fibrosis patients appear to absorb more of this saturated fatty acid than healthy children is not clear and requires further investigation.

Adolescent↗
PubMed2006

Ratio of oleic to palmitic acid is a dietary determinant of thrombogenic and fibrinolytic factors during the postprandial state in men.

BACKGROUND: The nature of dietary fats affects the postprandial activation of the hemostatic system. OBJECTIVE: We investigated whether the ratio of oleic to palmitic acid [and that of monounsaturated to saturated fatty acids (MUFA:SFA)] in the diet affects postprandial concentrations of triacylglycerols, tissue factor (TF), fibrinogen, tissue-type plasminogen activator (t-PA), and plasminogen activator inhibitor 1 (PAI-1). DESIGN: We studied the effects of diets enriched in olive oil (ROO), high-palmitic sunflower oil (HPSO), butter, or a mixture of vegetable and fish oils (VEFO) on circulating concentrations of the aforementioned factors in 14 healthy men. The fats had ratios of oleic to palmitic acid (MUFA:SFA) of 6.83 (5.43), 2.36 (2.42), 0.82 (0.48), and 13.81 (7.08). RESULTS: The largest and longest-lasting postprandial changes in plasma triacylglycerol concentrations were found with the butter-based diet (all P < 0.05). No correlation was observed between the net incremental area under the curve (netAUC) for triacylglycerol and the ratio of oleic to palmitic acid (or MUFA:SFA) in the dietary fats. The netAUCs for TF and PAI-1, however, were inversely related to the ratio of oleic to palmitic acid (and MUFA:SFA) in ROO, HPSO, butter, and VEFO. Similar results were found for the fibrinogen netAUC when VEFO was omitted from the analysis. The netAUC for t-PA was inversely correlated with postprandial concentrations of triacylglycerol. CONCLUSIONS: Postprandial concentrations of TF, fibrinogen, and PAI-1 are associated with the ratio of oleic to palmitic acid (MUFA:SFA) in dietary fats. The postprandial t-PA response is related to postprandial concentrations of triacylglycerol.

Adult↗
PubMed1995

The gastrointestinal handling and metabolism of [1-13C]palmitic acid in healthy women.

The gastrointestinal handling and metabolism of [1-13C]palmitic acid given as the free fatty acid was examined in six healthy women by measuring the excretion of 13C-label in stool and in breath as 13CO2. The gastrointestinal handling of [1-13C]palmitic acid was compared with the apparent absorption of dietary lipid by measuring lipid losses in stool. The variation both within and between subjects was determined by repeating the study in the same individuals on separate occasions. The time course for excretion of label in stool over the five-day study period followed a common pattern, with most of the label excreted over the first two days of the stool collection. 13C-Label excreted in stool over the five-day study period was 14.3 +/- 9.8% of that administered and on repeating the trial was 31.6 +/- 24.7% (not significantly different due to variability); there was poor agreement within subjects. Lipid excreted in stool expressed as a percentage of ingested lipid was 5.2 +/- 4.4% in Trial 1 and 5.9 +/- 4.0% in Trial 2, and was the same in each individual on repeating the trial. There was no clear relationship between the excretion of 13C-label and lipid in stool (Trial 1: R = -0.43, P > 0.40; Trial 2: R = -0.02, P > 0.97). On the first occasion, 22.0 +/- 4.5% of the administered label was excreted on breath over the 15-h study period and on repeating the trial was 15.8 +/- 9.5% (not significantly different) with poor repeatability in a given individual.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1975

Structure and synthesis of milk fat XI. Effects of heparin on paths of incorporation of glucose and palmitic acid into milk fat.

Intravenous injection of heparin increases lipoprotein lipase activity of circulating serum presumably by removing the enzyme from its location on the capillary endothelium. The incorporation of carbon-14 uniformly labeled glucose and carbon-14 1-labeled palmitic acid into fractionated milk fat triglycerides was studied in both normal and heparin treated lactating goats. The objective was to remove lipoprotein lipase from the mammary gland capillaries and to contrast normal milk fat synthesis with a situation presumed to cause the gland to be solely dependent on the phosphatidic acid pathway. The studies with labeled glucose indicated that under normal conditions there are two sources of milk glyceride glycerol; while following heparin injections, there is a single glycerol pool providing most of the glyceride glycerol. The investigations with labeled palmitic acid indicated that under normal conditions there are two sources of palmitic acid coming from the blood which enter nonequilibrating cellular pools. Palmitic acid from both pools is available for triglyceride synthesis. Following heparin injections there appears to be a common intracellular pool of pre-formed palmitic acid derived from the blood. The data indicate that lipoprotein lipase operating on blood triglycerides yields a 2-mono-glyceride which subsequently enters the gland and is utilized for milk fat synthesis.

Animals↗
PubMed1982

Influence of palmitic acid on mouse lymphocyte function in vivo and in vitro.

The effect of palmitic acid on the immune response of mice to sheep erythrocytes was studied. It was found to increase the number of background plaques in normal mice but it had no significant effect on primed cells. When given with antigen it functioned as a weak adjuvant but it had no effect on response of mouse lymphocytes to the mitogens phytohemagglutinin or bacterial lipopolysaccharide. While it is clear that palmitic acid does not have a profound effect on lymphocyte reactivity, it may have a subtle modulating influence on the immune system.

Adjuvants, Immunologic↗
PubMed1992

The origin of palmitic acid in brain of the developing rat.

A rat milk substitute containing lower amounts of palmitic and oleic acid in the triacylglycerols in comparison to natural rat milk was fed to artificially reared rat pups from day 7 after birth to day 14. Pups reared by their mother served as controls. Free trideuterated (D3) palmitic acid [(C2H3)(CH2)14COOH, 98 atom % D] and free perdeuterated (D31) palmitic acid [C15(2)H31COOH, 99 atom % D] in equal quantity were mixed into the triacylglycerols of the milk substitute in an amount equal to 100% of the palmitic acid in the triacylglycerols. A control milk substitute contained unlabeled free palmitic acid in an amount equal to 100% of the palmitic acid in the triacylglycerols of the milk substitute. The objective was to determine if palmitic acid in the diet contributed significantly to the palmitic acid content of developing brain and other organs. The methyl esters of the fatty acids were analyzed by gas chromatography and the palmitic acid methyl ester was examined by fast atom bombardment mass spectrometry. The proportion of deuterated methyl palmitate as a percentage of total palmitate was determined; 32% of the palmitic acid in liver and 12% of the palmitic acid in lung were trideuterated and perdeuterated palmitic acid in approximately equal amounts. The brain, by contrast, did not contain the deuterated palmitic acid moiety. Quantitation of palmitic acid and total fatty acids revealed a significant accumulation in organs in the interval from 7 to 14 days of age. Under our experimental conditions, labeled palmitic acid does not enter the brain. Consequently, we conclude that the developing brain produces all required palmitic acid by de novo synthesis.

Animals↗
PubMed1986

Enzymic acylation of mucus glycoprotein with palmitic acid in rat submandibular salivary gland.

The enzymic activity which catalyses transfer of palmitic acid from palmitoyl coenzyme A to mucus glycoprotein was found in Triton X-100 extracts of the microsomal fraction of rat submandibular and sublingual salivary glands. The acyltransferase activity of this fraction was 1.3-1.4 times greater in submandibular gland than in sublingual gland. Further subcellular fractionation of submandibular gland showed that the enzyme activity was associated with a Golgi-rich membrane fraction. Optimum enzyme activity for fatty acylation of mucus glycoprotein was at pH 7.4 using 0.5 per cent Triton X-100, 2 mM dithiothreitol 25 mM NaF and 10 mM MgCl2; higher concentrations were inhibitory. The apparent Km of the submandibular microsomal enzyme for mucus glycoprotein was 5.9 X 10(-7) M, and for palmitoyl-CoA, 3.3 X 10(-5) M. The 14C-labelled glycoprotein product of the reaction co-migrated on CsCl equilibrium, density-gradient centrifugation with submandibular mucus glycoprotein, and contained ester-bound palmitic acid. The fatty acyltransferase showed no activity with proteolytically-degraded glycoprotein; the acceptor capacity of reduced and S-carboxymethylated glycoprotein was only about 10 per cent lower than that of the intact mucus glycoprotein. This suggests that the acylation of salivary mucus glycoprotein with fatty acids occurs at its non-glycosylated, proteolysis-susceptible regions, and that the majority of these fatty acids are linked to the glycoprotein through hydroxyl esters.

Acylation↗
PubMed1995

Uptake and passage of beta-lactoglobulin, palmitic acid and retinol across the Caco-2 monolayer.

Caco-2 cell line grown on collagen coated polycarbonate membranes in bicameral chambers has been used to study the effect of the binding of palmitic acid or retinol on the uptake and passage of iodinated beta-lactoglobulin and albumin across cell monolayers. The percentage of beta-lactoglobulin transported through the monolayer was higher than that of albumin, about 50% and 30% of the total protein after 24 h of incubation, respectively. In all cases, less than 1% of protein was retained intracellularly. No differences were found in the uptake and transport of beta-lactoglobulin or albumin in the presence or absence of ligands. Furthermore, uptake and passage across Caco-2 monolayer of retinol or palmitic acid added either bound to beta-lactoglobulin or to albumin have been compared. The percentage of retinol found in the lower chamber was about 35% of the total retinol after 24 h of incubation for both proteins. However, the amount of retinol associated to cells was higher when it was added bound to beta-lactoglobulin than to albumin, about 26% and 10%, respectively. This fact suggests that the metabolic processing of retinol by Caco-2 cells is the rate-limiting step for retinol transport. The percentage of palmitic acid that crossed the monolayer was about 7%, remaining approx. 90% in the cells for beta-lactoglobulin and albumin. These data support the hypothesis that palmitic acid internalized by Caco-2 cells is mainly destined to serve the structural and energy needs. These results show evidence of retinol and palmitic uptake by Caco-2 cells when beta-lactoglobulin or albumin are the donors, and indicate that the type of binding protein does not affect the transport of both ligands through Caco-2 monolayer.

Biological Transport↗
PubMed2002

The omega-hydroxy palmitic acid induced apoptosis in human lung carcinoma cell lines H596 and A549.

We have found that omega-hydroxy palmitic acid (16-hydroxy palmitic acid, omega-HPA) has both cell growth inhibiting and cell death inducing actions on human lung adenosquamous carcinoma cell line H596 and adenocarcinoma cell line A549. Further, these effects were dose- and time-dependent in both cell lines. However, in squamous carcinoma cell line H226, omega-HPA had no cytotoxic effect. On the other hand, in the human small cell lung carcinoma (SCLC) cell line H128, this compound showed weak cytotoxicity. The sensitivity toward omega-HPA was higher in H596 cells than in A549 cells. In both H596 and A549 cells, cell growth was inhibited to 24.4 and 9.4%, respectively, by treatment with 100 microM omega-HPA for 12 h. In the 24 h treatment cells, growth inhibition was increased to 100 and 38.1%, respectively. In cytotoxicity experiments, the number of dead cells increased with incubation times in the presence of omega-HPA: on three days incubation with 100 microM omega-HPA, viability was 0 and 13.5%, respectively, in H596 and A549 cells. Further, the fragmentation of DNA to oligonucleosomal-sized ladder fragments, which is an index of apoptosis, was observed in both cell lines on treatment with omega-HPA. Therefore, it is assumed that these cell deaths induced by omega-HPA, were apoptosis in these cell lines. Since the number of dead cells following treatment with omega-HPA decreased by treatment with omega-HPA in combination with Z-VAD-fmk, a caspase family inhibitor, it is thought that apoptotic cell death was related to caspase activity.

Adenocarcinoma↗
PubMed1995

Dissolution rate of cholesterol and palmitic acid mixtures in cholelitholytic cosolvent systems.

The dissolution rates and solubilities of cholesterol monohydrate, palmitic acid, and their mixtures in the cholelitholytic solvents monooctanoin (MO) and methyl tert-butyl ether (MTBE) and mixtures of these two solvents were determined. The dissolution rates obtained were consistent with the diffusion-controlled two-component noninteracting model. The addition of MTBE as cosolvent to MO resulted in an increase in the solubility of both cholesterol monohydrate and palmitic acid; in the case of the former, the solubility peaked at 80% MTBE. Neither solute exhibited a log-linear solubility relationship on addition of MTBE as cosolvent. Furthermore the increases in the dissolution rates of both components were much larger than could be explained by the solubility increases alone. Mass transfer coefficients increased dramatically with increasing MTBE content of the solvent, were consistently higher for palmitic acid, and reflected the decline in solvent viscosity. Incorporation of relationships among solubility, viscosity, and cosolvent composition into the two-component noninteracting model gave good correlation between predicted and observed rates over nearly 3 orders of magnitude.

Caprylates↗