Search PubMed⌕ Search

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.

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

At least 1,567 records · Page 87Linked to original sources
PubMed1991

Fatty acid binding protein removes fatty acids but not phospholipids from microsomes liposomes and sonicated vesicles.

Evidence is provided in this paper that indicates that fatty acids but not phospholipids are removed from microsomes or artificial membranes (liposomes, unilamellar vesicles) by mouse liver cytosolic preparations enriched with fatty acid binding protein (FABP). The cytosolic proteins can act as acceptors for fatty acids but not for phospholipids of microsomal origin. Direct evidence came when liposomes made of egg yolk phosphatidylcholine, containing both [14C]labeled phospholipids and [1-14C] palmitic acid were incubated with FABP. Using sonicated vesicles as fatty acid or phospholipid donors, mouse liver fatty acid binding protein was capable of binding palmitic acid but not phospholipids. These studies suggest that liver fatty acid binding protein can interact with different kinds of membranes increasing specifically the desorption of fatty acids.

Animals↗
PubMed1997

Synthesis and purification of NB1-palmitoyl insulin.

A procedure for synthesizing NB1-palmitoyl insulin for incorporation into liposomes for targeting to hepatocytes was developed. The amino group of the first amino acid phenylalanine on the B chain (B1) of insulin was selected for conjugation with palmitic acid in anticipation that its binding to the insulin receptor would be preserved. Two other free amino groups present in insulin, the first amino acid glycine on the A chain (A1) and the 29th amino acid lysine on the B chain (B29), were first protected with a t-butoxycarbonyloxy (t-Boc) group to yield NA1, B29-di-(t-Boc) insulin. The identity of this di-(t-Boc) insulin was confirmed by amino acid analysis as well as by enzyme hydrolysis coupled with matrix-assisted laser-desorption time of flight mass spectrometry (MALDI-TOF MS). NA1,B29-Di-(t-Boc) insulin was then reacted with the N-hydroxysuccinimide ester of palmitic acid, followed by deblocking the t-Boc groups, to yield NB1-palmitoyl insulin, the structure of which was further confirmed by MALDI-TOF MS analysis. NB1-palmitoyl insulin was found to interact with the insulin receptor on fat cells, thereby catalyzing the conversion of [14C]glucose into lipids, at reduced efficiency (30-40%).

Animals↗
PubMed1980

[Development and comparison of lecithin/sphingomyelin and palmitic acid/stearic acid ratios in amniotic fluid].

Fetal lung maturity has been studied both by silica gel chromatography of phospholipids and gas liquid chromatography of fatty acids. Lecithin/sphingomyelin (L/S) ratios and palmitic/stearic (P/S) ratios were compared. A good correlation was obtained. However, when the L/S ratio has an intermediate value (1.5 less than or equal to L/S less than 2) making it difficult to judge the fetal lung maturity, the P/S ratio expresses the lung maturity more accurately.

Amniotic Fluid↗
PubMed1993

Effect of growth temperature on the fatty acid composition of Mycobacterium phlei.

In Mycobacterium phlei, fatty acid unsaturation increased with decreasing temperature. The 10-hexadecenoic acid content increased as the temperature was reduced from 35 degrees C to 26-20 degrees C. At lower temperatures tuberculostearic acid decreased while oleic and linoleic acids increased, the latter being found in M. phlei for the first time. Concomitantly palmitic acid content decreased, and the 6- and 9-hexadecenoic acids increased slightly on reducing the temperature from 35 to 10 degrees C. Thus, down to 26-20 degrees C palmitic acid was mainly replaced by 10-hexadecenoic acid. From this range down to 10 degrees C, palmitic and tuberculostearic acids were replaced by oleic and linoleic acids. Consequently, fatty acid branching decreased and mean chain length increased, as the temperature was reduced. These observations support the view that regulation of membrane fatty acid composition is part of microbial temperature adaptation, and that the mechanism behind the responses might be more complex than generally believed.

Fatty Acids↗
PubMedDate not supplied

The fatty acid pattern of triglycerides in liver, adipose tissue and serum of diabetics with hyperlipoproteinemia before and during clofibrate treatment.

In 20 diabetic inpatients with type IIb, III, IV and V hyperlipoproteinemia (HPL) the triglyceride fatty acid pattern (TFAP) of serum, adipose tissue and liver biopsy specimens before and after one year of clofibrate treatment has been determined by gas-liquid chromatography. Compared to previous results which revealed a correlation between fat droplet size and the TFAP in liver parenchyma cells, remarkable changes were observed after long-term therapy. In adipose tissue, only linoleic acid increased significantly from 8.6 to 11.3%. In serum, myristic and palmitic acid decreased, whereas linoleic, eicosatetraenoic (arachidonic) and eicosapentaenoic acid rose significantly. In liver fat, palmitic acid decreased, whereas linoleic, eicosatrienoic, arachidonic and eicosapentaenoic acid significantly increased. After clofibrate therapy, the TFAP in diabetic subjects with HLP became similar to that of diabetics without HLP. The most pronounced changes were found in the liver, serum having an intermediate position between liver and adipose tissue. The pathophysiological relevance in view of possible relations to prostaglandins has been discussed.

Adipose Tissue↗
PubMed1997

Stimulation of mitochondrial fatty acid oxidation by growth hormone in human fibroblasts.

In vivo administration of GH induces lipolysis and lipid oxidation. However, it is not clear whether the stimulation of lipid oxidation is a direct effect of GH or is driven by increased substrate supply secondary to lipolysis. An in vitro bioassay has been established for assessing beta-oxidation of fatty acids in mitochondria, based on the measurement of conversion of tritiated palmitic acid to 5H2O by fibroblasts in culture. We have modified this assay to investigate whether GH stimulates fatty acid oxidation. GH stimulated oxidation of palmitic acid maximally by 26.7 +/- 2.5% (mean +/- SEM; P < 0.0001). The stimulation was biphasic, with the oxidation rate increasing with increasing GH concentration to a peak response at 1.5 nmol/L and declining to a level not significantly different from control thereafter. Insulin-like growth factor-I at concentrations of up to 250 nmol/L had no significant effect on fatty acid oxidation. GH-binding protein attenuated the effect of GH. An anti-GH receptor (GHR) antibody (MAb263), which dimerizes the receptor and induces GH-like biological actions, significantly stimulated fatty acid oxidation. Another anti-GHR antibody (MAb5), which prevents receptor dimerization, suppressed GH action. In summary, GH directly stimulated fatty acid oxidation, an action not mediated by insulin-like growth factor-I. Dimerization of GHRs was necessary for this effect. This bioassay is a practical tool for studying the regulatory effects of GH on lipid oxidation.

Antibodies, Monoclonal↗
PubMed1996

X-ray diffraction analysis of isolated skin lipids: reconstitution of intercellular lipid domains.

Low- and wide-angle X-ray diffraction were used to determine the structural organization of lipids isolated from the stratum corneum extracellular matrix that forms the major water permeability barrier in mammalian epidermis. Hydrated pig skin ceramides gave a single low-angle reflection of about 62 angstroms and a wide-angle-reflection at 4.15 angstroms. The addition of either cholesterol or fatty acid, the other major lipid components of the skin stratum corneum extracellular matrix, modified this diffraction pattern, depending on the lipid mole ratios. In the absence of water, lipid mixtures exhibited lipid phase separation, as shown by low- and wide-angle reflections typical of a separate cholesterol phase. However, a hydrated 2:1:1 mole ratio of ceramide:cholesterol:palmitic acid (similar to that found in stratum corneum) produced a diffraction pattern with a single sharp wide-angle reflection at 4.10 angstroms and low-angle reflections which indexed as the first eight orders of a single repeat period of 130 angstroms. The repeat period and intensity distribution of the low-angle data were similar to those found in intact stratum corneum [White et al. (1988) Biochemistry 27, 3725-3732; Bouwstra et al. (1994) Biochim. Biophys. Acta 1212, 183-192]. Higher concentrations of cholesterol or palmitic acid resulted in lipid phase separations. The 130 angstrom repeat period decreased only about 3 angstroms as water was removed by incubation in low-relative humidity atmospheres. The 130 angstrom repeat period depended on the presence of a particular ceramide, N-(omega-acyloxy)-acylsphingosine, which is found only in the epidermis. In contrast, 2:1:1 mixtures of brain ceramide:cholesterol:palmitic acid gave reflections of 56 and 34 angstroms. These results indicate that a structure with dimensions similar to those of the lamellar repeating unit found in skin stratum corneum does not depend on the presence of protein but does depend on the presence of specific skin ceramides and appropriate concentrations of cholesterol and fatty acid.

Animals↗
PubMed1996

Pharmacological effects of phosphatidylserine enzymatically synthesized from soybean lecithin on brain functions in rodents.

Soybean transphosphatidylated phosphatidylserine (SB-tPS) was prepared from soybean phosphatidylcholine by transphosphatidylation using phospholipase D, and the fatty acids composition and pharmacological properties were compared with those of bovine brain cortex-derived phosphatidylserine (BC-PS) which was reported to improve cognitive disorders of senile dementia patients by oral administration (300 mg/day). The molecular species of SB-tPS are rich in linoleic and palmitic acids whereas those of BC-PS are stearic and oleic acids. Despite the differences in fatty acid composition, SB-tPS displayed significant activities on the increase in brain glucose concentrations in mice (79 mg/kg, i.v.) and the restoration of scopolamine-induced amnesia in rats (60 mg/kg, i.p.) as did BC-PS. These results suggest the possibility that SB-tPS may prevent and/or improve senile dementia by oral administration.

Amnesia↗
PubMed1995

Free fatty acid analysis in ascitic fluid improves diagnosis in malignant abdominal tumors.

The fasting concentration of free fatty acids (FFA) in the ascitic fluid was determined in 14 patients with malignant ascites and in 19 patients with liver cirrhosis. In malignant ascites FFA levels were increased more than three times when compared with the levels in cirrhotic ascites (5.241 +/- 0.493 vs. 1.558 +/- 0.170 mumol/ml; P < 0.0001). Palmitic acid was the most representative saturated FFA (which together accounted for 2.499 +/- 0.323 vs. 0.833 +/- 0.064 mumol/ml; P < 0.0001), while unsaturated FFA (2.741 +/- 0.298 vs. 0.725 +/- 0.111 mumol/ml; P < 0.001) were represented, in decreasing order, by oleic, linoleic and arachidonic acids. The ratio of unsaturated to saturated FFA was higher in neoplastic patients (1.35 +/- 0.29 vs. 0.826 +/- 0.065 P < 0.05). Albumin concentration in ascitic fluid of neoplastic patients was 22.44 +/- 1.35 g/l, while that of cirrhotic patients was 8.19 +/- 0.32 g/l, P < 0.0001. A close relationship (R2 = 95.14%) between albumin concentration in ascitic fluid and levels of total FFA was found. These data support the hypothesis that the elevation of FFA in ascitic fluid allows discrimination between malignant and non-malignant ascites.

Adult↗
PubMed2004

Protective role of Phaseolus vulgaris on changes in the fatty acid composition in experimental diabetes.

The present investigation was carried out to evaluate the effect of Phaseolus vulgaris, an indigenous plant used in Unani and Ayurvedic medicine in India, on blood glucose, plasma insulin, cholesterol, triglycerides, free fatty acids, phospholipids, and fatty acid composition of total lipids in liver, kidney, and brain of normal and streptozotocin (STZ) diabetic rats. The results show that there was a significant increase in tissue cholesterol, triglycerides, free fatty acids, and phospholipids in STZ diabetic rats. The analysis of fatty acids showed that there was a significant increase in the concentrations of palmitic acid (16:1), stearic acid (18:0), and oleic acid (18:1) in liver, kidney, and brain, whereas the concentrations of linolenic acid (18:3) and arachidonic acid (20:4) were significantly decreased. Oral administration of the aqueous extract of P. vulgaris pods (200 mg/kg of body weight) for 45 days to diabetic rats decreased the concentrations of lipids and fatty acids, viz., palmitic, stearic, and oleic acids, whereas linolenic and arachidonic acids were elevated. Similarly, the administration of P. vulgaris pod extract (PPEt) to normal animals resulted in a significant hypolipidemic effect. These results suggest that PPEt exhibits hypoglycemic and hypolipidemic effects in STZ diabetic rats. It also prevents the fatty acid changes produced during diabetes. The effect of PPEt at 200 mg/kg of body weight was better than that of glibenclamide.

Animals↗
PubMed1990

Phosphatidylcholine stimulates the activity of UDP-Gal beta 1-4 galactosyltransferase in normal human kidney proximal tumour cells.

Effects of various lipid components of low density lipoproteins (LDL) and serine on the regulation of UDP-Gal-beta 1-4-galactosyltransferase (GalT-2) activity have been investigated in normal proximal tubular (PT) cells. Addition of exogenous serine (0.1-0.75 mM), cholesterol (0-200 micrograms/ml medium), linoleic acid and oleic acid (0.1-0.75 mM) for 4 hr at 37 degrees C did not suppress the activity of GalT-2 in PT cells. Similarly, incubation of cells with glucosylceramide and lactosylceramide (25-50 micrograms/ml medium) did not alter GalT-2 activity in cells as compared to control. In contrast, palmitic acid (0-0.75 mM), phosphatidylethanolamine and sphingomyelin (0-200 micrograms/ml) stimulated GalT-2 activity by 20-36% as compared to control. Incubation of PT cells with D-alpha-dipalmitoyl phosphatidylcholine (0-200 micrograms/ml medium) also stimulated the activity of GalT-2, maximum stimulation (200%) occurring with 25 micrograms phosphatidylcholine/ml medium. However, at a higher concentration (200 micrograms/ml), the stimulation of the activity of GalT-2 was in the order of 27% compared to control. Dioleylphosphatidylcholine did not alter GalT-2 activity in PT cells. Thus, it is concluded that (i) various lipid components, sphingosine and serine present in LDL are not involved in the LDL-mediated suppression of GalT-2 activity in normal PT cells, and (ii) stringent structural requirements in the phosphatidylcholine molecule are necessary to exert a time and concentration dependent stimulation of GalT-2 activity.

Cells, Cultured↗
PubMed1985

Fatty acid acylation of salivary mucin in rat submandibular glands.

The acylation of salivary mucin with fatty acids and its biosynthesis was investigated by incubating rat submandibular salivary gland cells with [3H]palmitic acid and [3H]proline. The elaborated extracellular and intracellular mucus glycoproteins following delipidation, Bio-Gel P-100 chromatography, and CsCl equilibrium density gradient centrifugation were analyzed for the distribution of the labeled tracers. Both preparations gave single bands at the CsCl density of 1.48, in which carbohydrate peaks coincided with that of the labels. The [3H]palmitic acid in these glycoproteins was susceptible to cleavage by alkali and hydroxylamine, thus indicating the ester nature of the bond. With both intracellular and extracellular glycoproteins deacylation caused the glycoproteins to band in the CsCl gradient at a density of 1.55. The incorporation of both markers into mucus glycoprotein increased steadily with time up to 4 h, at which time about 65% of [3H]palmitate and [3H]proline were found in the extracellular glycoprotein and 35% in the intracellular glycoprotein. The incorporation ratio of proline/palmitate, while showing an increase with incubation time in the extracellular glycoprotein, remained essentially unchanged with time in the intracellular glycoprotein and at 4 h reached respective values of 0.14 and 1.12. The fact that the proline/palmitate incorporation ratio in the intracellular glycoprotein at 1 h of incubation was 22 times higher than in the extracellular and 8 times higher after 4 h suggests that acylation occurs intracellularly and that fatty acids are added after apomucin polypeptide synthesis. As the incorporation of palmitate within the intracellular mucin was greater in the mucus glycoprotein subunit, it would appear that fatty acid acylation of mucin subunits preceeds their assembly into the mucus glycoprotein polymer.

Acylation↗
PubMed1990

High-resolution electron density profiles reveal influence of fatty acids on bilayer structure.

Small-angle x-ray diffraction studies were performed on gel phase-oriented bilayers of dipalmitoylphosphatidylcholine (DPPC) and DPPC containing 40 mol% of either palmitic acid (PA) or palmitic acid brominated at the 2-position (BPA). Oriented samples were prepared using a method developed by us, which is as simple as powder sample preparations while offering all the advantages of oriented samples made by traditional methods. Phases were determined using swelling experiments with structure factors plotted in reciprocal space, creating a relatively smooth curve as the amount of water between the bilayers was changed. Continuous Fourier transforms were also calculated to further test the consistency of the phase assignments. The diffraction data were used to calculate absolute electron density profiles for different bilayers to a resolution of 5-6 A. Analysis indicates the following: (a) The electron density profiles for the three preparations are virtually identical in the hydrocarbon chain region. (b) There is a decrease in the electron density of the glycerol backbone-headgroup region and d-space in DPPC-PA compared to DPPC. (c) The bromine of fatty-acid brominated at the 2-position is in the vicinity of the glycerol backbone. (d) The bilayer thickness of DPPC containing either brominated or unbrominated fatty acid remains relatively constant with increased levels of hydration, unlike DPPC bilayers.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1985

Effect of insulin on the oxidative desaturation of fatty acids in non-diabetic rats and in isolated liver cells.

The effect of insulin on the oxidative desaturation of 1-14C palmitic acid to palmitoleic acid (delta 9 desaturase) 1-14C linoleic acid to alpha-linolenic acid (delta 6 desaturase) on rat liver microsomes and 1-14C eicosa-8,11,14-trienoic acid to arachidonic acid (delta 5 desaturase) on rat liver microsomes and hepatoma tissue culture (HTC) cells was studied. After 12 h of insulin injection, at a dose of 2.5-12.5 U/kg no change was found in delta 9 desaturation activity while delta 5 desaturation activity decreased. The conversion of linoleic to alpha-linolenic acid decreased when the amount of insulin injected was 5 U/kg or more. The effect of insulin (5 U/kg) on delta 9, delta 6 or delta 5 desaturation activity was tested from 1 to 12 h after the injection. The conversion of palmitic acid to palmitoleic acid showed no important changes along the time, while delta 5 desaturation activity decreased at all the times tested. delta 6 Desaturation activity showed a slight increase after 1 h of insulin treatment and then decreased significantly up to the end of the experiment. The addition of 400 mU/ml or more of insulin to the incubation medium of HTC cells produced a significant decrease on the conversion of eicosatrienoic acid to arachidonic acid. The effect of insulin on fatty acid desaturation activity of liver microsomes of normal rats differs from that of diabetic rats. The role of this hormone in relation to other hormones, carbohydrate metabolism and lipid biosynthesis on the activity of the desaturases was discussed.

8,11,14-Eicosatrienoic Acid↗
PubMed1989

Species recognition elicited by differences in composition of the genital sex pheromone in Dermacentor variabilis and D. andersoni (Acari: Ixodidae).

The chemical basis for the ability of fed males of Dermacentor variabilis (Say) and D. andersoni (Stiles) to differentiate conspecific and heterospecific females was investigated using a neutered female bioassay. Male D. variabilis responded strongly in a dose-response manner to increasing concentrations of stearic and palmitic acids and an extract of the anterior reproductive tract (ART) of fed D. variabilis females. Mating responses were greatest at 1 microgram of fatty acid and 1 female equivalent (FE) of ART extract. D. variabilis males also responded strongly to D. variabilis females treated with a conspecific ART extract and a mixture of fatty acids simulating the extract; responses were moderate to D. andersoni females treated with the same extract or fatty acid mixture. They also responded moderately to conspecific females treated with D. andersoni extract. Male D. andersoni displayed moderate increases in mating behavior over a range of concentrations of stearic and palmitic acids and conspecific ART extract. D. andersoni males mated only with D. andersoni females treated with a conspecific extract or a mixture of fatty acids simulating the extract. Mating by D. andersoni did not occur in response to D. variabilis females treated with D. andersoni or D. variabilis ART extracts. Stearic acid alone or in combination with 20-hydroxyecdysone, oleic, or myristic acid did not account for the specificity of response of either species. D. andersoni males were much less responsive to fatty acids, alone or in mixtures, than D. variabilis males. These findings indicate that fatty acids are important in mate recognition by D. variabilis, but explain only part of that by D. andersoni. The possibility is raised that another compound is required for mate recognition by D. andersoni.

Animals↗
PubMed1980

Evaluation of fetal pulmonary maturity by gas-chromatographic analysis of amniotic fluid palmitic acid/stearic acid (P/S) ratio.

Gas-chromatographic analysis of the fatty acids (P/S ratio) in 212 samples of amniotic fluid, 35 samples of vernix caseosa and 35 samples of the pellets obtained after centrifugation of the amniotic fluid were carried out to evaluate the effects of contaminants that might be present in amniotic fluid on the P/S ratio. The P/S ratio is used as an index of the degree of maturity of the fetal or neonatal lungs. Analysis of variance applied to the means of the P/S values for each of above materials showed them to be significantly different and attests to the importance of centrifugation for obtaining valid results. We propose a standard procedure of centrifugation for 60 minutes at 3500 X g followed by extraction and gas-chromatography as a rapid, valid way to measure the P/S ratio.

Amniotic Fluid↗
PubMedDate not supplied

Selected metabolic results of the Leipzig gerontological longitudinal study.

The results of the longitudinal study show a gradual development of the overweight of young obese women. The decrease of weight in middle aged obese women is likely to be influenced by additional therapeutic measures by the physicians. It is interesting to note that men and women of normal weight do not develop overweight over a ten-years-span. Serum cholesterol increased in all age and weight groups within a ten-years-interval. The changes of the shares of total fatty acids were especially characterized by the decrease of palmitic acid and the increase of linoleic acid in the ten-years-interval. However age, weight and sex differences were present. The increase of uric acid level occurred with all test persons independent of sex. With test persons above 45 years a significant sex difference was noticed.

Adult↗
PubMed1993

Recovery of regional contractile function and oxidative metabolism in stunned myocardium induced by 1-hour circumflex coronary artery stenosis in chronically instrumented dogs.

Stunned myocardium produced by 1 hour of critical coronary artery stenosis was evaluated for alteration in regional mechanical function and overall oxidative and fatty acid metabolism by positron emission tomography (PET) in chronically instrumented dogs. Twenty-seven dogs, chronically instrumented for measurements of left ventricular pressure and regional myocardial wall thickening in normal and ischemic zones, were subjected to a 1-hour period of myocardial ischemia produced by graded left circumflex coronary artery stenosis, resulting in minimal residual flow. Mean transmural myocardial flow during 1-hour coronary stenosis decreased to 0.34 +/- 0.04 ml/min per gram in the ischemic zones (normal zone transmural flow, 0.96 +/- 0.10 ml/min per gram). Systolic wall thickening in the ischemic zone was almost completely abolished (-97 +/- 4%). On reperfusion, systolic wall thickening immediately resumed but remained depressed. Progressive recovery was noted with time. At 24 hours, systolic wall thickening was still depressed (-20 +/- 6%, p < 0.01). At 1 week, wall thickening had completely recovered and was no longer significantly different from the control condition. In addition, the absence of necrosis at the site of wall thickness measurements was confirmed at autopsy in all dogs. No abnormalities were found by electron microscopy in four dogs undergoing myocardial biopsies at the time of PET studies. Dynamic PET studies using [1-11C]acetate tracer (performed at 6 hours, 1 week, and 2 weeks after reperfusion) and [1-11C]palmitic acid tracer (performed at 6 hours, 12 hours, 24 hours, 1 week, and 2 weeks after reperfusion) allowed the computation of regional tissue time-activity curves in different regions of interest at different times during follow-up. Despite full reperfusion, abnormal [1-11C]acetate and [1-11C]palmitic acid kinetics were observed in the posterior segments, previously subjected to ischemia, as evidenced by a significant decrease in the slope of the early 11C clearance curve component. Repeat PET studies revealed progressive normalization of overall oxidative metabolism and fatty acid metabolism, which paralleled the time course of recovery of mechanical function. Thus, myocardial ischemia, produced by 1-hour coronary artery stenosis, followed by full reperfusion is associated with a prolonged period of postischemic mechanical and metabolic dysfunction. This transient reduction in oxygen delivery induced a prolonged impairment in fatty acid beta-oxidation as well as a reduction in overall oxidative metabolism despite full reoxygenation. A similar time course for recovery of function and metabolism was observed.

Acetates↗