Palmitic acid concentration in amniotic fluid: a modified method to aid prediction of fetal lung maturity.
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Amniotic Fluid↗
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Results for “PALMITIC ACID”
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Inhibitory effect of Mg2+ on the protonophoric activity of palmitic acid.
To discriminate whether fatty acids are uncouplers that cause acceleration of State-4 respiration, associated with a decrease in the protonmotive force, or decouplers that increase respiration without associated decrease in the protonmotive force, we examined the effect of palmitate on functions of rat-liver mitochondria under various conditions. We found that palmitate itself increases State-4 respiration, releases oligomycin-inhibited State-3 respiration, inhibits ATP synthesis and ATP<->Pi exchange reaction, and increases H+ permeability in mitochondrial and model bilayer phospholipid membranes. Thus, palmitate is a classical uncoupler of oxidative phosphorylation. However, these effects were inhibited by Mg2+, due to rapid formation of a stable complex between palmitate and Mg2+.
Animals↗
Palmitic acid concentration of amniotic fluid in diabetic pregnancy.
The fatty acid composition of total lipid and phospholipid contents was determined in the amniotic fluid of normal and diabetic pregnant patients. Disturbance of lipid metabolism which is not related to the severity of diabetes, causes difficulties in the determination of L/S ratio. The palmitic acid content of total lipid and lecithin is increased in diabetic pregnancy. The lecithin synthesis is significantly decreased as result of a transitory or prolonged acidosis.
Acidosis↗
Salient effects of L-carnitine on adenine-nucleotide loss and coenzyme A acylation in the diabetic heart perfused with excess palmitic acid. A phosphorus-31 NMR and chemical extract study.
The beneficial effects of L-carnitine perfusion on energy metabolism and coenzyme A acylation were studied in isolated hearts from control and diabetic rats. All hearts were perfused at a constant flow rate with a glucose/albumin buffer which contained 2.0 mM palmitate. 31P-NMR was utilized to assess sequential phosphocreatine and ATP metabolism during 1 h of recirculation perfusion. L-Carnitine (5.0 mM final concentration) was added after 12 min of baseline recirculation perfusion. Frozen samples were taken after 1 h of recirculation perfusion for spectrophotometric analysis of high-energy phosphates and the free and acylated fractions of coenzyme A. L-Carnitine perfusion of diabetic hearts attenuated or prevented the reduction of ATP observed in untreated diabetic hearts. It also attenuated the accumulation of long-chain fatty-acyl coenzyme A. Although L-carnitine improved myocardial function in diabetic hearts, this was independent of any direct effect on physiological indices. Thus, the salutory effect of acute perfusion with L-carnitine on energy metabolism in the isolated perfused diabetic rat heart appears to be a direct effect on lipid metabolism.
Acyl Coenzyme A↗
Mixed monolayers of alkylated azacrown ethers and palmitic acid at the air-water surface.
The Langmuir films of two alkylated azacrown ethers at the air-water surface were characterized using surface pressure-area isotherms, ellipsometry, Brewster angle microscopy, and constant-area surface pressure relaxation. The azacrown ether molecules aggregate in the monolayer, which significantly stabilizes the film against dissolution. Mixed azacrown ether-palmitic acid monolayers were also characterized; results suggest that at high compression the two molecules interact repulsively. The influence of Cu(II) ions present in the aqueous subphase on the single components and mixed monolayer characteristics was also studied.
Cations, Divalent↗
The effects of DDT, DDOH-palmitic acid, and a chlorinated paraffin on muscarinic receptors and the sodium-dependent choline uptake in the central nervous system of immature mice.
Ten-day-old NMRI mice were given a single peroral dose of 1.4 mumol/kg body wt of either of the substances of DDT (0.5 mg), DDOH-PA (a DDT metabolite conjugated to palmitic acid; 0.7 mg), or polychlorohexadecane (PCHD, a synthesized chlorinated paraffin; 1.0 mg). The mice were killed either 24 hr or 7 days after treatment, and crude synaptosomal fractions (P2) were prepared from the cerebral cortex and hippocampus. The density of the muscarinic receptors was assayed by measuring quinuclidinyl benzilate ([3H]QNB) specifically bound in the P2 fraction. A significant increase in the specific [3H]QNB binding was observed in the cerebral cortex in DDT- and DDOH-PA-treated mice 7 days after treatment, compared to control. These results were further explored by determining the ratio of high- and low-affinity binding sites by using an agonist (carbachol)-antagonist ([3H]QNB) competition assay. A significant decrease in the percentage of high-affinity binding sites and a corresponding increase in the percentage of low-affinity binding sites, compared to control, were observed after DDT and DDOH-PA treatment. The presynaptically sodium-dependent choline uptake system also was studied. In mice receiving PCHD there was a significant decrease (65%) in the Vmax value 7 days after treatment, but no change was observed in mice receiving DDT or DDOH-PA. This study shows that the sensitivity of the cholinergic system to persistent xenobiotics acting over a long period of time may be higher in the immature mouse.
Animals↗
A method for quantitative acylcarnitine profiling in human skin fibroblasts using unlabelled palmitic acid: diagnosis of fatty acid oxidation disorders and differentiation between biochemical phenotypes of MCAD deficiency.
Inherited disorders of fatty acid oxidation are a group of acute life-threatening but treatable disorders, clinically complicated by severe hypoketotic hypoglycemia precipitated by prolonged fasting. Among them, medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is by far the most frequent disorder. Here we report a modified method for quantitative acylcarnitine profiling by electrospray ionisation-tandem mass spectrometry (ESI-MS-MS) in human skin fibroblasts using unlabelled palmitic acid as substrate. The reliability of this method was tested in cultured skin fibroblasts from previously diagnosed patients with specific carnitine cycle and fatty acid beta-oxidation defects. Furthermore, acylcarnitine profiling was investigated in fibroblasts and dried blood spots from patients with different variants of MCAD deficiency. ESI-MS-MS-based investigation of cultured skin fibroblasts from patients with disorders of fatty acid oxidation revealed a pathognomonic acylcarnitine profiling. In addition, this method delineated different variants of MCAD deficiency, i.e. mild and classical. The octanoylcarnitine (C8)-to-decanoylcarnitine (C10) and C8-to-acetylcarnitine (C2) ratios were the most specific markers to differentiate mild and classical forms of MCAD deficiency in fibroblasts. Similar results were obtained by quantitative acylcarnitine profiling in dried blood spots. In conclusion, this novel technique is a powerful tool for the investigation of fatty acid oxidation disorders under standardized conditions in fibroblasts.
Acyl-CoA Dehydrogenase↗
Oral absorption of insulin encapsulated in artificial chyles of bile salts, palmitic acid and alpha-tocopherol dispersions.
The hypoglycemic effect of orally given insulin was studied on rabbits, using different bile salts as absorption promoters, in two different carriers to form an artificial chyloform system ready to be absorbed by intestinal mucosa. The rank order of enhancement by bile salts in the presence of 1% ethanol was deoxycholate>cholate>glycocholate>glycodeoxycholate>taurodeoxycholate>no bile salts. The dose response studies with increased insulin loaded in the chyle showed a greater corresponding hypoglycemic effect with the system of cholate-palmitic-alpha-tocopherol dispersions than the cholate-palmitic acid dispersions. A more effective hypoglycemic effect was achieved using lower doses of the deoxycholate-palmitate-tocopherol-chyle dispersions.
Administration, Oral↗
2-Dodecylcyclobutanone, a radiolytic product of palmitic acid, is genotoxic in primary human colon cells and in cells from preneoplastic lesions.
The irradiation of fat results in the formation of 2-alkylcyclobutanones, a new class of food contaminants. Results of previous in vitro studies with primary human colon cells and in vivo experiments with rats fed with 2-alkylcyclobutanones indicated that these radiolytic derivatives may be genotoxic and enhance the progression of colon tumors. The underlying mechanisms of these effects, however, are not clearly understood. Therefore we performed additional investigations to elucidate the genotoxic potential of 2-dodecylcyclobutanone (2dDCB) that is generated from palmitic acid. In particular, we explored the relative sensitivities of human colon cells, representing different stages of tumor development and healthy colon tissues, respectively. HT29clone19A cells, LT97 adenoma cells and primary human epithelial cells were exposed to 2dDCB (150-2097 microM). We determined cytotoxic effects using trypan blue exclusion. Genotoxicity, reflected as strand breaks, was assessed using the alkaline version of the comet assay and chromosomal abnormalities were investigated by 24-color fluorescence-in-situ-hybridization. 2dDCB was cytotoxic in a time- and dose-dependent manner in LT97 adenoma cells and in freshly isolated primary cells but not in the human colon tumor cell line. Associated with this was a marked induction of DNA damage by 2dDCB in LT97 adenoma cells and in freshly isolated colonocytes, whereas in the HT29clone19A cells no strand breaks were detectable. A long-term incubation of LT97 adenoma cells with lower concentrations of 2dDCB revealed cytogenetic effects. In summary, 2dDCB was clearly genotoxic in healthy human colon epithelial cells and in cells representing preneoplastic colon adenoma. These findings provide additional evidence that this compound may be regarded as a possible risk factor for processes in colon carcinogenesis related to initiation and progression.
Cell Line, Tumor↗
The pharmacological screening of Pentanisia prunelloides and the isolation of the antibacterial compound palmitic acid.
The uses of Pentanisia prunelloides in Zulu traditional medicine indicate that the plant is believed to be effective in relieving inflammation, bacterial and viral infections and also stimulating uterine contraction. Aqueous, ethanolic and ethyl acetate extracts of leaves and roots were screened for prostaglandin-synthesis inhibitors and antibacterial and antiviral activity. In the results of the anti-inflammatory assay all the extracts showed cyclooxygenase-1 inhibition. The ethanolic and ethyl acetate extracts showed greater antibacterial activity than the aqueous extracts against Gram-positive (Bacillus subtilis, Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae). Both root and leaf extracts were found to inhibit viral replication of the Influenza A virus. The ethyl acetate extract was fractionated by silica vacuum liquid chromatography and anti-inflammatory activity was found to be most pronounced in the more polar fractions. The presence of antibacterial activity was confirmed by running the fractions on a thin layer chromatography (TLC) plate and performing a bioautographic assay. The active fraction was further purified by TLC and the major antibacterial compound in the ethyl acetate root extract was identified by GC/MS as palmitic acid.
Anti-Bacterial Agents↗
Canine myocilin is associated with lipid modified by palmitic acid.
PURPOSE: Myocilin, the product of the GLC1A locus in humans, has been associated with primary open angle glaucoma (POAG). Mutations in myocilin exon 3 correlate with age of onset and severity of POAG. Myocilin has been under investigation in experimentally induced glaucoma in rats, mice, and monkeys, however no animal model of inherited POAG exists except in beagles. Our aim was to determine whether canine myocilin more closely resembles human myocilin than does myocilin from other species. METHODS: Canine myocilin was cloned and sequenced from beagle ocular tissues and Madin-Darby Canine Kidney (MDCK) cells, a well characterized canine cell line. Immunohistochemistry was performed on beagle tissues and cultured canine ocular primary cells. RT-PCR was employed to analyze genes expressed by tissues and cells. Myocilin protein synthesized by MDCK and canine optic nerve head cells (ONH) was analyzed by metabolic radioisotope labeling. Immunoprecipitation, enzymatic digestion, and Triton X-114 phase separation were performed to determine the carbohydrate content and the hydrophobicity of canine myocilin, respectively. RESULTS: Canine ONH astrocytes cultured from a beagle eye expressed myocilin and markers of type 1B astrocytes observed also in human ONH cells in culture. The sequence of canine myocilin showed close similarity with the human sequence but lacked the additional upstream coding region found only in human and rat. Myocilin was labeled with (3)H palmitic acid. This label co-eluted with (35)S label in hydroxylapatite chromatography despite purification by phase separation in Triton X-114, immunoprecipitation with myocilin-specific sera, and denaturing conditions of heat, SDS, and reducing agent. CONCLUSIONS: Canine myocilin revealed no striking sequence differences from myocilin of other species. Mutations in myocilin of glaucomatous beagles may suggest a similar pattern of involvement in inherited POAG. This represents the first report of lipid associated with the myocilin protein. Many lipid-modified proteins reside in lipid rafts. This modification of myocilin with lipids supports the unusual secretion properties and may suggest a function of myocilin in sorting, cell signaling and communication between the extracellular matrix and the cell membranes.
Amino Acid Sequence↗
Biosynthesis of gangliosides containing C18:1 and C20:1 [3-14C]sphingosine after administrating [1-14C]palmitic acid and [1-14C]stearic acid to rat cerebellar granule cells in culture.
The biosynthesis of ganglioside molecular species containing sphingosine of different structure was investigated by administrating rat cerebellar granule cells in culture with [1-14C]palmitic and [1-14C]stearic acids which are the precursors for sphingosine biosynthesis. The incorporation of radioactivity into the sphingosine of the ganglioside species containing C20:1 sphingosine after administrating [1-14C]stearic acid was low in comparison with the incorporation of radioactivity into the sphingosine of ganglioside species containing C18:1 sphingosine after administration of [1-14C]palmitic acid, but the ratio between the radioactivity incorporated in the C20:1 and the C18:1 sphingosine of C20 and C18 ganglioside species progressively increased when the cell culture was prolonged. Ceramide-containing radioactive sphingosine was found after palmitic or stearic acid administration. Ceramide-containing C20:1 sphingosine found after adding stearic acid was about 5% of that synthesized starting from palmitic acid and containing C18:1 sphingosine. Free radioactive C18:1 and C20:1 sphingosine were found after adding radioactive palmitic or stearic acid. This is representative of a catabolic process occurring after biosynthesis of the complex sphingolipid starting from the radioactive precursor. In fact it has been proved that only saturated sphingosines are used for the synthesis of complex sphingolipids, the introduction of the double bond at position four of the sphingoid chain occurring at the level of ceramide [Rother, J., van Echten, G., Schwarzmann, G. & Sandhoff, K. (1992) Biochem. Biophys. Res. Commun. 189, 14-20]. Saturated sphingosines were not present. The lack of free C20:0 sphingosine confirms the hypothesis that the C20:0 sphingosine synthesis and the process (C20:0 sphingosine-->C20:0 ceramide-->C20:1 ceramide) occur in the correct quantity for the synthesis of C20:1 gangliosides. Moreover, we found only traces of free C20:1 sphingosine, at days 8 and 15 of cell culture when the biosynthesis of complex C20:1 gangliosides and the related catabolic processes occur to a higher extent, thus excluding the idea that a large amount of C20:0 sphingosine can be acylated to C20:0 ceramide and dehydrogenated to C20:1 ceramide which, being not used for ganglioside biosynthesis, is immediately catabolised to C20:1 sphingosine.
Animals↗
Effects of prostaglandins E2 and F2alpha (PGE2; PGF2alpha), trilostane, mifepristone, palmitic acid (PA), indomethacin (INDO), ethamoxytriphetol (MER-25), PGE2 + PA, or PGF2alpha + PA on PGE2, PGF2alpha, and progesterone secretion by bovine corpora lutea of mid-pregnancy in vitro.
The effects of PGE2, PGF2alpha, trilostane, RU-486, PA, INDO, MER-25, PGE2, or PGF2alpha + PA on secretion of progesterone, PGE2, or PGF2alpha by bovine corpora lutea (CL) of mid-pregnancy in vitro for 4 and 8 hr was examined. Secretion of PGE2 and PGF2alpha increased with time in culture (P < or = 0.05). PGE2 and PGE2 + PA increased (P < or = 0.05) secretion of progesterone at 4 and 8 h, progesterone secretion was increased (P < or = 0.05) at 4 h; but not at 8 h (P > or = 0.05) by trilostane, mifepristone, PGF2alpha and PGF2alpha + PA, and was decreased at 8 h by PGF2alpha and PGF2alpha + PA. Indomethacin decreased (P < or = 0.05) secretion of PGE2, PGF2alpha, and progesterone at 4 and 8 h. Trilostane, PA, PGF2alpha, RU-486 and PGF2alpha + PA increased (P < or = 0.05) PGE2 at 4 h only. Palmitic acid decreased (P < or = 0.05) PGF2alpha at 4 h, while trilostane, RU-486, or MER-25 did not affect (P < or = 0.05) PGE2 of PGF2alpha secretion. It is concluded that PGE2 of luteal tissue origin is the luteotropin at mid-pregnancy in cows. Also, it is suggested that PA may alter progesterone secretion by affecting the inter conversion of PGE2 and PGF2alpha.
Abortifacient Agents, Steroidal↗
An autoradiographic study of the in-vivo incorporation of [3H]-palmitic acid into the dentine and enamel lipids of rat incisors, with a comparison of rapid-freezing freeze-substitution fixation and aldehyde fixation.
Four and twenty-four hours after injection of the labelled precursor, there were twice as many silver grains scored with the cryotechniques as with conventional fixation. Absence of labelled-band formation in dentine, the diffusion of silver throughout the entire thickness of dentine as well as the layer of forming enamel. This suggests that lipids are membrane-associated components rather than true matrix-associated components.
Aldehydes↗
In vivo fatty acid utilization of the dog abdominal organs: uptake and metabolism of (1-14C)-palmitic acid in the dog liver.
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Animals↗
Enhancement of Agkistrodon piscivorus piscivorus venom phospholipase A2 activity toward phosphatidylcholine vesicles by lysolecithin and palmitic acid: studies with fluorescent probes of membrane structure.
The activity of phospholipase A2 from snake venom to hydrolyze bilayers of phosphatidylcholines is greatly enhanced by the presence of the hydrolysis products, lysolecithin and fatty acid, in the bilayer. The fluorescence of several probes of membrane structure was used to monitor changes in bilayer physical properties during vesicle hydrolysis. These changes were compared to emission spectra and fluorescence polarization results occurring upon direct addition of lysolecithin and/or fatty acid to the bilayer. The excimer to monomer ratio of 1,3-bis(1-pyrene)propane was insensitive to vesicle hydrolysis, suggesting that changes in the order of the phospholipid chains were not relevant to the effect of the hydrolysis products on phospholipase activity. The fluorescence of 6-propionyl-2-(dimethylamino)-naphthalene (Prodan) suggested that the polarity of the bilayer in the region of the phospholipid head groups increases as the hydrolysis products accumulate in the bilayer. The fluorescence of 6-dodecanoyl-2-(dimethylamino)naphthalene (Laurdan) confirmed that such effects were restricted to the bilayer surface. Furthermore, the lysolecithin appeared to be the product most responsible for these changes. These results suggested that lysolecithin increases the activity of phospholipase A2 during vesicle hydrolysis by disrupting the bilayer surface, making the phospholipid molecules more accessible to the enzyme active site.
2-Naphthylamine↗
A mutant of Arabidopsis deficient in desaturation of palmitic Acid in leaf lipids.
The overall fatty acid composition of leaf lipids in a mutant of Arabidopsis thaliana was characterized by elevated amounts of palmitic acid and a decreased amount of unsaturated 16-carbon fatty acids as a consequence of a single nuclear mutation. Quantitative analysis of the fatty acid composition of individual lipids suggested that the mutant is deficient in the activity of a chloroplast omega9 fatty acid desaturase which normally introduces a double bond in 16-carbon acyl chains esterified to monogalactosyldiacylglycerol (MGD). The mutant exhibited an increased ratio of 18- to 16-carbon fatty acids in MGD due to a change in the relative contribution of the prokaryotic and eukaryotic pathways of lipid biosynthesis. This appears to be a regulated response to the loss of chloroplast omega9 desaturase and presumably reflects a requirement for polyunsaturated fatty acids for the normal assembly of chloroplast membranes. The reduction in mass of prokaryotic MGD species involved both a reduction in synthesis of MGD by the prokaryotic pathway and increased turnover of MGD molecular species which contain 16:0.
Journal Article↗
Effects of temperature and glycerides on the enhancement of Agkistrodon piscivorus piscivorus phospholipase A2 activity by lysolecithin and palmitic acid.
The effect of temperature and various glycerides to modulate the ability of lysolecithin and fatty acid to promote high phospholipase A2 activity was studied using dipalmitoylphosphatidylcholine large unilamellar vesicles as substrate. The length of the lag phase prior to the accumulation of sufficient hydrolysis products (lysolecithin and fatty acid) to support high phospholipase activity was shortest at temperatures near the thermotropic phase transition of the phospholipid substrate. A reduction in the lag phase correlated with a reduction in the requirement for hydrolysis products at the phase transition temperature, where the bilayer exists in a state of fluctuating domains of gel and liquid crystal. Dipalmitoylglycerol and tripalmitoylglycerol also reduced the length of the lag phase. This reduction was both concentration-dependent and temperature-dependent relative to the phase transition in the presence of the glycerides. As with the effect of temperature, the ability of di- and triglycerides to decrease the lag time correlated with a decrease in the amount of reaction products necessary to promote high phospholipase activity. This effect coincided with the tendency of the glycerides to form domains in the bilayer. Glycerides that did not form domains either had no effect (monopalmitoylglycerol) or increased the length of the lag phase (dicaprylglycerol). These data suggest that the effect of the reaction products to increase phospholipase A2 activity is aided by the presence of fluctuations in lipid domains within the bilayer.
Agkistrodon↗