Search Results
Results 401 - 450 of 2631
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Wei Yuan - - 2004
We used the patch-clamp technique to study the effect of arachidonic acid (AA) on epithelial Na channels (ENaC) in the rat cortical collecting duct (CCD). Application of 10 microM AA decreased the ENaC activity defined by NPo from 1.0 to 0.1. The dose-response curve of the AA effect on ENaC ...
Kowluru Anjaneyulu - - 2004
Long-chain fatty acids (e.g. arachidonic acid) have been implicated in physiological control of insulin secretion. We previously reported histidine phosphorylation of at least two islet proteins (e.g., NDP kinase and the beta subunit of trimeric G-proteins), and suggested that such a signalling step may have regulatory roles in beta cell ...
Buckler K J - - 2005
TREK-1 is a member of the two-pore domain potassium (K(2P)) channel family that is mechano-, heat, pH, voltage and lipid sensitive. It is highly expressed in the central nervous system and probably encodes one of the previously described arachidonic acid-activated K(+) channels. Polyunsaturated fatty acids and lysophospholipids protect the brain ...
Caley Alex J - - 2005
Two-pore-domain potassium channels are a family of ion channels that are widely believed to play an important role in maintaining and regulating neuronal excitability. It has been shown that they can be modulated by an extraordinarily diverse range of endogenous and exogenous factors. One particular member of the family, TREK-1 ...
Zhang David X - - 2005
We recently reported that the lipoxygenase product 11,12,15-trihydroxyeicosatrienoic acid (THETA) mediates arachidonic acid (AA)-induced relaxation in the rabbit aorta. This study was designed to determine whether this lipoxygenase metabolite is involved in relaxation responses to AA in rabbit small mesenteric arteries. AA (10(-9)-10(-4) M) produced potent relaxations in isolated phenylephrine-preconstricted ...
Levine Lawrence - - 2004
I have postulated that arachidonic acid release from rat liver cells is associated with cancer chemoprevention. Since it has been reported that inhibition of proteasome activities may prevent cancer, the effects of proteasome inhibitors on arachidonic acid release from cells and on prostaglandin I2 production in rat liver cells were ...
Fang Xiang - - 2004
We investigated the effects of soluble epoxide hydrolase (sEH) inhibition on epoxyeicosatrienoic acid (EET) metabolism in intact human blood vessels, including the human saphenous vein (HSV), coronary artery (HCA), and aorta (HA). When HSV segments were perfused with 2 micromol/l 14,15-[3H]EET for 4 h, >60% of radioactivity in the perfusion ...
Zhang David X - - 2004
The present study characterizes the vascular responses of isolated small bovine adrenal cortical arteries to acetylcholine, an endogenous neurotransmitter in the adrenal gland. Acetylcholine (10(-10) to 10(-6) m) elicited a concentration-dependent relaxation, with a maximal relaxation of 96 +/- 1% and EC50 of 4.2 nm. The relaxation was abolished by ...
Saitoh Hiroto - - 2004
An excised patch membrane sensor for arachidonic acid (AA) is described, whose response stems from AA-induced channel-type transport of ions across the excised patch membrane. The patch membrane sensor was prepared in situ by excising mouse hippocampal cell membranes with patch pipets having a tip diameter of < 0.5 microm. ...
DeBarber Andrea E - - 2004
Studies have shown that mammalian cytochromes p450 participate in the metabolism of terpenes, yet their role in the biotransformation of farnesol, an endogenous 15-carbon isoprenol, is unknown. In this report, [(14)C]-farnesol was transformed to more polar metabolites by NADPH-supplemented mammalian microsomes. In experiments with microsomes isolated from acetone-treated animals, the ...
Tanabe Michiharu - - 2004
The current study assessed the differential incorporation of 12-hydroperoxyeicosatetraenoic acid (12-HPETE), arachidonic acid (AA), 12-hydroxyeicosatetraenoic acid (12-HETE) and the linoleic acid (LA) oxidation products, 13-hydroxyoctadecadienoic acid (13-HODE) and 13-hydroperoxyoctadecadienoic acid (13-HPODE), into human umbilical vein endothelial cells (HUVEC). Approximately 80-90% of AA (10(-8)-10(-5)M) and 80% of LA (10(-8)-10(-5)M) were incorporated ...
Tirapelli Carlos R - - 2004
The present work describes the mechanisms involved in the vasorelaxant effect of the diterpene ent-kaur-16-en-19-oic acid (kaurenoic acid). Kaurenoic acid (10, 50 and 100 microM) concentration-dependently inhibited phenylephrine and KCl-induced contraction in either endothelium-intact or -denuded rat aortic rings. Kaurenoic acid also reduced CaCl(2)-induced contraction in Ca(2+)-free solution containing KCl ...
Le Quéré Valérie - - 2004
CYP4F isoforms are involved in the oxidation of important cellular mediators such as leukotriene B4 (LTB4) and prostaglandins. The proinflammatory agent LTB4 and cytotoxic leukotoxins have been associated with several inflammatory diseases. We present evidence that the hydroxylation of Z 9(10)-epoxyoctadecanoic, Z 9(10)-epoxyoctadec-Z 12-enoic, and Z 12(13)-epoxyoctadec-Z 9-enoic acids and ...
Amemiya Tsugio - - 2004
PURPOSE: The purpose of this study was to demonstrate fatty acids in the rat retina and to show that time-of-flight secondary ion mass spectrometry (TOF-SIMS) can replace histochemistry. METHODS: Five normal 3-month-old Wistar Kyoto rats were used. The eyes were enucleated under pentobarbital anesthesia, immediately put into liquid nitrogen without ...
Garcia Eloi S - - 2004
Hemocoelic inoculation of epimastigotes of Trypanosoma rangeli strain H14 into 5th-instar larvae of Rhodnius prolixus previously fed on blood containing the same parasites, showed reduced number of hemocyte microaggregates in the hemolymph, enhanced number of flagellates in the hemolymph as well as increased mortality of these insects. All these effects ...
Cui Xiaoxuan - - 2004
OBJECTIVE: Sepsis is characterized by an early, hyperdynamic phase and a late, hypodynamic phase. Although studies have shown that cytochrome P450 (CYP) plays an important role in the regulation of vascular reactivity, alterations of vascular CYP isoforms in sepsis remain unknown. Since CYP2C11 and CYP2J4 convert arachidonic acid to vasodilative ...
DeLozier Tracy C - - 2004
The human CYP2Cs have been studied extensively with respect to the metabolism of clinically important drugs and endogenous chemicals such as arachidonic acid (AA). Five members of the mouse CYP2C family have previously been described that metabolize arachidonic acid into regio- and stereospecific epoxyeicosatrienoic acids (EETs) and hydroxyeicosatetraenoic acids, which ...
Sarkis Albert - - 2004
PURPOSE OF REVIEW: Cytochrome P-450 metabolites of arachidonic acid have been reported to play an important role in the control of renal function and vascular tone, and in the long-term control of arterial pressure. In this regard, 20-hydroxyeicosatetraenoic acid is a potent vasoconstrictor that inhibits sodium reabsorption in the kidney. ...
McCowen Karen C - - 2004
Despite absence of essential fatty acid deficiency (EFAD), increases in arachidonic acid to linoleic acid ratios occur in serum phospholipid of patients treated with chronic total parenteral nutrition (TPN). The parenteral lipid component of TPN contains abundant linoleate; thus low phospholipid linoleate may reflect increased conversion to arachidonate. Arachidonic acid ...
Roy Uzzal - - 2004
Trans-arachidonic acids (trans-AA) are products of cis-trans isomerization of arachidonic acid by nitrogen dioxide radical (NO(2)), and occur in vivo, but their metabolism is unknown. We found that hepatic microsomes oxidized trans-AA via cytochrome P450/NADPH system to epoxides, which were hydrolyzed by epoxide hydrolase to diols (DiHETEs). 14,15-trans-AA produced one ...
Vance Russell E RE Department of Microbiology and Molecular Genetics, Center for Genomic Applications and Therapeutics, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, - - 2004
In mammals, lipoxygenases play key roles in inflammation by initiating the transformation of arachidonic acid into potent bioactive lipid mediators such as leukotrienes and lipoxins. In general, most bacteria are believed to lack lipoxygenases and their polyunsaturated fatty acid substrates. It is therefore of interest that an ORF (PA1169) with ...
Leslie Christina C - - 2004
Mammalian cells have developed specific pathways for the incorporation, remodeling, and release of arachidonic acid. Acyltransferase and transacylase pathways function to regulate the levels of esterified arachidonic acid in specific phospholipid pools. There are several distinct, differentially regulated phospholipases A2 in cells that mediate agonist-induced release of arachidonic acid. These ...
Nakamura Hiroyuki - - 2004
Sphingolipid metabolites such as sphingosine 1-phosphate (S1P) and ceramide can mediate many cellular events including apoptosis, stress responses and growth arrest. Although ceramide stimulates arachidonic acid metabolism in several cells, the effects of sphingosine and its endogenous analogs have not been established. We investigated the effects of D-erythro-sphingosine and its ...
Yang M S - - 2004
Abstract Metabolomic analysis is a technology which seeks to provide a comprehensive profile of all the metabolites present in a biological sample ( Fiehn 2002 ; Noguchi et al. 2003 ; Watkins et al. 2002 ). Metabolomics is not a new science, but emerging as an exciting application which can ...
Kramer Brian C - - 2004
The contribution of arachidonic acid (AA) release and metabolism to the toxicity that results from glutathione (GSH) depletion was studied in rat mesencephalic cultures treated with the GSH synthesis inhibitor l-buthionine sulfoximine. Our data show that GSH depletion is accompanied by increased release of AA, which is phosholipase A2 (PLA2) ...
Zhu M - - 2004
AIMS: To develop a fast isolation method for arachidonic acid-producing fungi of high yield. METHODS AND RESULTS: Relation between the staining degree of mycelia of Mortierella alpina stained with triphenyltetrazolium chloride (TTC) and arachidonic acid content in the fungal lipids was investigated. Results showed that staining degree of mycelia stained ...
Dymkowska Dorota - - 2004
The unsaturated fatty acids oleic acid and arachidonic acid induced typical apoptosis in Ehrlich ascites tumor cells harvested at the stationary growth phase. Arachidonic acid was a more potent inducer than oleic acid. Apoptosis was induced by concentrations of oleic and arachidonic acids that produced only partial uncoupling of the ...
Gauthier Kathryn M - - 2004
Arachidonic acid induces an endothelium-dependent relaxation of the rabbit aorta that is blocked by lipoxygenase inhibitors. The cellular vasodilatory mechanisms activated by arachidonic acid metabolites remain undefined. In rabbit thoracic aortic rings pretreated with indomethacin (10 micromol/L) and contracted with phenylephrine, arachidonic acid (0.1 to 100 micromol/L) induced concentration-dependent relaxations. ...
Li Quanxi - - 2004
The 12/15-lipoxygenases (12/15-LOX) catalyze the stereo-specific oxygenation of arachidonic and linoleic acids into a complex series of signaling molecules, including the hydroxyeicosatetraenoic acids (HETEs) and hydroxyoctadecadienoic acids (HODEs). Our previous studies, using high density oligonucleotide microarrays, suggested a novel link between progesterone receptor (PR) signaling and 12/15-LOX-mediated fatty acid metabolism ...
Nakashima Satoru - - 2003
sPLA(2)s (secretory phospholipases A(2)) belong to a broad and structurally diverse family of enzymes that hydrolyse the sn -2 ester bond of glycerophospholipids. We previously showed that a secreted fungal 15 kDa protein, named p15, as well as its orthologue from Streptomyces coelicolor (named Scp15) induce neurite outgrowth in PC12 ...
Feinmark Steven J - - 2003
Arachidonic acid metabolites have been proposed as signaling molecules in hippocampal long-term potentiation (LTP) and long-term depression (LTD) for >15 years. However, the functional role of these molecules remains controversial. Here we used a multidisciplinary biochemical, electrophysiological, and genetic approach to examine the function of the 12-lipoxygenase metabolites of arachidonic ...
Chuang Samuel S - - 2004
Long chain fatty acids have recently emerged as critical signaling molecules in neuronal, cardiovascular, and renal processes, yet little is presently known about the precise mechanisms controlling their tissue distribution and bioactivation. We have identified a novel cytochrome P450, CYP2U1, which may play an important role in modulating the arachidonic ...
Pfister Sandra L - - 2003
Previous work showed that rabbit aorta metabolizes arachidonic acid via 15-lipoxygenase to 15-hydroperoxyeicosatetraenoic acid (15-HPETE), which undergoes an enzymatic rearrangement to 11-hydroxy-14,15-epoxyeicosatrienoic acid (11-H-14,15-EETA) and 15-hydroxy-11,12-epoxyeicosatrienoic acid (15-H-11,12-EETA). Hydrolysis of the epoxy group results in the formation of 11,14,15- and 11,12,15-trihydroxyeicosatrienoic acids (THETAs). Endothelial cells have several heme-containing enzymes including ...
Xu Fengyun - - 2004
Arachidonic acid is omega-hydroxylated to 20-hydroxyeicosatetraenoic acid (20-HETE), which has effects on vasoactivity and renal tubular transport and has been implicated in the regulation of blood pressure. Cytochrome p450 (p450) 4A isoforms are generally considered the major arachidonic acid omega-hydroxylases; however, little is known about the role of rat CYP4F ...
Saitoh Masaru - - 2003
The present study aimed at understanding the effects of arachidonic acid peroxides on neuronal cell death using the mouse neuroblastoma cell line, Neuro-2A cells. Arachidonic acid peroxides were produced by ultraviolet (UV) radiation. UV-radiated arachidonic acid significantly reduced Neuro-2A cell viability at concentrations of more than 0.1 muM, with being ...
Kaduce Terry L - - 2004
We have investigated the role of endothelial cells in the metabolism of 20-hydroxyeicosatetraenoic acid (20-HETE), a vasoactive mediator synthesized from arachidonic acid by cytochrome P450 omega-oxidases. Porcine coronary artery endothelial cells (PCEC) incorporated 20-[(3)H]HETE primarily into the sn-2 position of phospholipids through a coenzyme A-dependent process. The incorporation was reduced ...
Jones Raymond - - 2003
Colorectal carcinoma is a leading cause of cancer related death worldwide. This deadly disease advances through a series of clinical and histopathological stages, initiated by single crypt lesions to small benign tumors and finally to malignancy. Although some progress has been made in elucidating the formation of colorectal tumors at ...
Miller Paula - - 2004
Expression of the human tandem P domain K+ channel, hTREK1, is limited almost exclusively to the central nervous system, where ambient Po2 can be as low as 20 Torr. We have previously shown that this level of hypoxia evokes a maximal inhibitory influence on recombinant hTREK1 and occludes the activation ...
Danthi S - - 2003
The modulation of TREK-1 leak and Kv1.4 voltage-gated K+ channels by fatty acids and lysophospholipids was studied in bovine adrenal zona fasciculata (AZF) cells. In whole-cell patch-clamp recordings, arachidonic acid (AA) (1-20 microM) dramatically and reversibly increased the activity of bTREK-1, while inhibiting bKv1.4 current by mechanisms that occurred with ...
Sacerdoti David - - 2003
Arachidonic acid (AA) can undergo monooxygenation or epoxidation by enzymes in the cytochrome P450 (CYP) family in the brain, kidney, lung, vasculature, and the liver. CYP-AA metabolites, 19- and 20-hydroxyeicosatetraenoic acids (HETEs), epoxyeicosatrienoic acids (EETs) and diHETEs have different biological properties based on sites of production and can be stored ...
Faas F H - - 2003
OBJECTIVE: To measure prostatic and blood fatty acid composition in a large group of patients undergoing prostatectomy for benign or malignant prostate disease, as there is evidence linking arachidonic acid metabolism and prostate cancer through its role as an eicosanoid precursor, and earlier studies showed lower prostatic arachidonic acid content ...
Levine Lawrence - - 2003
Tamoxifen is widely prescribed for the treatment of breast cancer. Its success has been attributed to the modulation of the estrogen receptor. I have previously proposed that the release of arachidonic acid from cells may also mediate cancer prevention. Rat liver cells were radiolabelled with arachidonic acid. The release of ...
Gauthier Kathryn M - - 2003
Endothelium-dependent hyperpolarizations and relaxation of vascular smooth muscle induced by acetylcholine and bradykinin are mediated by endothelium-derived hyperpolarizing factors (EDHFs). In bovine coronary arteries, arachidonic acid metabolites, epoxyeicosatrienoic acids (EETs), function as EDHFs. The 14,15-EET analog 14,15-epoxyeicosa-5(Z)-enoic-methylsulfonylimide (14,15-EEZE-mSI) was synthesized and tested for agonist and antagonist activity. In U46619-preconstricted bovine ...
Okita Misako - - 2003
OBJECTIVES: An abnormal fatty acid pattern in patients with advanced liver cirrhosis (LC) has been reported in plasma phospholipids and some other tissues. To elucidate the significance of arachidonic acid deficiency on the clinical pathophysiology of LC and hepatocellular carcinoma (HCC), we analyzed the fatty acid compositions of mononuclear cell ...
Pérez-Matute P - - 2003
Leptin, a hormone produced in adipocytes, is a key signal in the regulation of food intake and energy expenditure. Several studies have suggested that leptin can be regulated by macronutrients intake. Arachidonic acid is a dietary fatty acid known to affect cell metabolism. Controversial effects of this fatty acid on ...
Vogan Claire L - - 2003
The barnacle life cycle has two key stages at which eicosanoids are believed to be involved in cellular communication pathways, namely the hatching of nauplii and the settlement of cypris larvae. Barnacle egg-hatching activity has previously been reported to reside in a variety of eicosanoids, including 8-hydroxyeicosapentaenoic acid and a ...
Tang Xin - - 2003
OBJECTIVE: Vasorelaxation of rabbit aorta is mediated by factors released from the vascular endothelium. In the aortic endothelium, arachidonic acid (AA) is metabolized via the 15-lipoxygenase pathway to the vasodilatory compounds 11,12,15-trihydroxyeicosatrienoic acid (THETA) and 15-hydroxy-11,12-epoxyeicosatrienoic acid (HEETA). Interleukin-13 (IL-13) increases 15-lipoxygenase expression and activity in several types of cells. ...
Pomposiello Silvia I - - 2003
We have shown a cytochrome P450-dependent renal vasodilator effect of arachidonic acid in response to inhibition of cyclooxygenase and elevation of perfusion pressure, which was enhanced in the spontaneously hypertensive rat (SHR) and linked to increased production of and/or responsiveness to epoxyeicosatrienoic acids (EETs). In the SHR, vasodilation elicited by ...
Petersen Rasmus K - - 2003
Arachidonic acid inhibits adipocyte differentiation of 3T3-L1 cells via a prostaglandin synthesis-dependent pathway. Here we show that this inhibition requires the presence of a cAMP-elevating agent during the first two days of treatment. Suppression of protein kinase A activity by H-89 restored differentiation in the presence of arachidonic acid. Arachidonic ...
Akakabe Yoshihiko - - 2003
Marine green alga Ulva conglobata was investigated for the biogeneration of oxygenated products from exogenously added arachidonic acid (ARA). A crude enzyme from the alga afforded the detectable amount of a hydroperoxyicosatetraenoic acid (HPITE), which was identified as (R)-11-HPITE by HPLC and GC-MS. Headspace-SPME method indicated that ARA was selectively ...
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