Enhanced synthesis of epoxyeicosatrienoic acids by cholesterol-fed rabbit aorta

1991 ◽  
Vol 261 (3) ◽  
pp. H843-H852 ◽  
Author(s):  
S. L. Pfister ◽  
J. R. Falck ◽  
W. B. Campbell
Keyword(s):  
Arachidonic Acid ◽  
Mass Spectra ◽  
Acid Metabolism ◽  
Rabbit Aorta ◽  
Arachidonic Acid Metabolism ◽  
Gas Chromatography Mass Spectrometry ◽  
Epoxyeicosatrienoic Acids ◽  
Aortic Tissue ◽  
Cytochrome P 450 ◽  
Hydroxyeicosatetraenoic Acids

Arachidonic acid metabolism via cyclooxygenase, lipoxygenase, and cytochrome P-450 epoxygenase was investigated in thoracic aortic tissue obtained from rabbits fed either standard rabbit chow or chow containing 2% cholesterol. Aortic strips were incubated with [14C]arachidonic acid and A23187. Metabolites from extracted media were resolved by high-pressure liquid chromatography (HPLC). Normal and cholesterol-fed rabbit aortas synthesized prostaglandins (PGs) and hydroxyeicosatetraenoic acids (HETEs). The major cyclooxygenase products were 6-keto-PGF1 alpha and PGE2. Basal aortic 6-keto-PGF1 alpha production was slightly reduced in cholesterol-fed compared with normal rabbits. 12(S)- and 15(S)-HETE were the major aortic lipoxygenase products from both normal and cholesterol-fed rabbits. The structures were confirmed by gas chromatography-mass spectrometry (GC-MS). Only cholesterol-fed rabbit aortas metabolized arachidonic acid via cytochrome P-450 epoxygenase to the epoxyeicosatrienoic acids (EETs). 14,15-, 11,12-, 8,9-, and 5,6-EET were identified based on comigration on HPLC with known 14C-labeled standards and typical mass spectra. Incubation of normal aorta with 14,15-EET decreased the basal synthesis of 6-keto-PGF1 alpha. The other EETs were without effect. The four EET regioisomers relaxed the norepinephrine-precontracted normal and cholesterol-fed rabbit aorta. The relaxation response to 14,15-EET was greater in aortas from cholesterol-fed rabbits. These studies demonstrate that hypercholesterolemia, before the development of atherosclerosis, alters arachidonic acid metabolism via both the cyclooxygenase and epoxygenase pathways.

The interaction Between Arachidonic Acid Metabolism and Homocysteine

2020 ◽  
Vol 20 ◽  
Author(s):  
Elisa Domi ◽  
Malvina Hoxha ◽  
Bianka Hoxha ◽  
Bruno Zappacosta
Keyword(s):  
Cardiovascular Disease ◽  
Arachidonic Acid ◽  
Acid Metabolism ◽  
Neurological Diseases ◽  
Arachidonic Acid Metabolism ◽  
Epoxyeicosatrienoic Acids ◽  
Pathological Conditions ◽  
Literature Searches ◽  
Hydroxyeicosatetraenoic Acids ◽  
Improve Health

Purpose: Hyperhomocysteinemia (HHcy) has been considered a risk factor for different diseases including cardiovascular disease (CVD), inflammation, neurological diseases, cancer and many other pathological conditions. Likewise, arachidonic acid (AA) metabolism is implicated in both vascular homeostasis and inflammation as shown by the development of CVD following the imbalance of its metabolites. Aim of The Review: This review summarizes how homocysteine (Hcy) can influence the metabolism of AA. Methods: In silico literature searches were performed on PubMed and Scopus as main sources. Results: Several studies have shown that altered levels of Hcy, through AA release and metabolism, can influence the synthesis and the activity of prostaglandins (PGs), prostacyclin (PGI₂), thromboxane (TXA), epoxyeicosatrienoic acids (EETs) and hydroxyeicosatetraenoic acids (HETEs). Conclusions: We believe that by targeting Hcy in AA pathways, novel compounds with better pharmacological and pharmacodynamics benefits may be obtained and that this information is valuable for dietician to manipulate diets to improve health.

Fluorescent HPLC assay for 20-HETE and other P-450 metabolites of arachidonic acid

2000 ◽  
Vol 279 (2) ◽  
pp. H863-H871 ◽  
Author(s):  
Kristopher G. Maier ◽  
Lisa Henderson ◽  
Jayashree Narayanan ◽  
Magdalena Alonso-Galicia ◽  
John R. Falck ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Interstitial Fluid ◽  
Internal Standard ◽  
Dienoic Acid ◽  
Renal Tissue ◽  
Gas Chromatography Mass Spectrometry ◽  
Epoxyeicosatrienoic Acids ◽  
Hplc Assay ◽  
Standard Curve ◽  
Cytochrome P 450

This study describes a fluorescent HPLC assay for measuring 20-hydroxyeicosatetraenoic acid (20-HETE) and other cytochrome P-450 metabolites of arachidonic acid in urine, tissue, and interstitial fluid. An internal standard, 20-hydroxyeicosa-6( Z),15( Z)-dienoic acid, was added to samples, and the lipids were extracted and labeled with 2-(2,3-naphthalimino)ethyl trifluoromethanesulfonate. P-450 metabolites were separated on a C18 reverse-phase HPLC column. Coelution and gas chromatography-mass spectrometry studies confirmed the identity of the 20-HETE peak. The 20-HETE peak can be separated from those for dihydroxyeicosatrienoic acids, other HETEs, and epoxyeicosatrienoic acids. Known amounts of 20-HETE were used to generate a standard curve (range 1–10 ng, r 2 = 0.98). Recovery of 20-HETE from urine averaged 95%, and the intra-assay variation was <5%. Levels of 20-HETE were measured in 100 μl of urine and renal interstitial fluid or 0.1 mg of renal tissue. The assay was evaluated by studying the effects of 1-aminobenzotriazole (ABT) on the excretion of 20-HETE in rats. ABT reduced excretion of 20-HETE by >65% and inhibited the formation of 20-HETE by renal microsomes. The availability of this assay should facilitate work in this field.

Lipoxygenase-dependent superoxide release in skeletal muscle

2004 ◽  
Vol 97 (2) ◽  
pp. 661-668 ◽  
Author(s):  
Li Zuo ◽  
Fievos L. Christofi ◽  
Valerie P. Wright ◽  
Shengying Bao ◽  
Thomas L. Clanton
Keyword(s):  
Skeletal Muscle ◽  
Arachidonic Acid ◽  
Cytochrome C ◽  
Acid Metabolism ◽  
Arachidonic Acid Metabolism ◽  
Anion Channels ◽  
Cytochrome C Reduction ◽  
First Time ◽  
Cytochrome P 450 ◽  
Different Sources

Superoxide anion radical (O2•−) is released from skeletal muscle at rest and is particularly elevated during conditions of heat stress (42°C). Previous studies have shown that in isolated rat diaphragm O2•− release is not dependent on mitochondrial electron transport, reduced NADP oxidase activity, or the integrity of membrane anion channels. This study hypothesized that O2•− release, as measured by cytochrome c reduction, is linked to metabolism of arachidonic acid. Phospholipase A2 inhibition with manoalide significantly decreased O2•− release. In downstream pathways, neither the blockage of cyclooxygenase with indomethacin nor the inhibition of cytochrome P-450-dependent monooxygenase with SKF-525A decreased O2•− release. However, lipoxygenase (LOX) inhibition with general LOX blockers 5,8,11,14-eicosatetraynoic acid and cinnamyl-3,4-dihydroxy-α-cyanocinnamate greatly attenuated the signal. Furthermore, the specific 5-LOX inhibitor diethylcarbamazine also significantly decreased O2•− release. Immunohistochemistry localized 5- and 12-LOX to the cytosol and sarcolemma of muscle cells. Confocal studies, using the O2•−-sensitive fluorescent indicator hydroethidine, demonstrated that LOX inhibition had no significant influence on intracellular O2•− formation. When compared with the cytochrome c results, this indicates that intra- and extracellular O2•− must arise from different sources. These data show for the first time that arachidonic acid metabolism through LOX activity, is a major source of extracellular O2•− release in skeletal muscle.

Role of cytochrome P-450 4A in oxygen sensing and NO production in rat cremaster resistance arteries

1999 ◽  
Vol 277 (4) ◽  
pp. H1546-H1552 ◽  
Author(s):  
Cornel J. M. Kerkhof ◽  
Erik N. T. P. Bakker ◽  
Pieter Sipkema
Keyword(s):  
Arachidonic Acid ◽  
Acid Metabolism ◽  
Arachidonic Acid Metabolism ◽  
No Production ◽  
Cremaster Muscle ◽  
Resistance Arteries ◽  
Arterial Diameter ◽  
Spontaneous Tone ◽  
Cytochrome P 450

The role of arachidonic acid metabolism and nitric oxide (NO) in hypoxia-induced changes of vascular tone was investigated in first-order cannulated rat cremaster muscle resistance arteries. Spontaneous tone reduced arterial diameter from 179 ± 2 μm (fully dilated) to 98 ± 3 μm under normoxia ([Formula: see text] = 150 mmHg). Hypoxia ([Formula: see text] 5–10 mmHg) had no significant effect on arterial diameter under conditions of spontaneous tone. The effect of hypoxia was not changed after blockade of cyclooxygenase with indomethacin or after blockade of lipoxygenase with nordihydroguaiaretic acid. However, after partial blockade of cytochrome P-450 4A enzymes with 17-octadecynoic acid (17-ODYA), hypoxia increased the diameter by 65 ± 6 μm ( P < 0.05). This increase could be inhibited by N G-nitro-l-arginine (l-NNA) or 20-hydroxyeicosatetraenoic acid (20-HETE). 17-ODYA induced a concentration-dependent dilation under normoxia, which could be blocked by endothelium removal orl-NNA. 17-ODYA did not increase smooth muscle sensitivity to NO. We conclude that, under conditions of spontaneous tone and in the absence of luminal flow, hypoxia (5–10 mmHg) has no effect on the diameter of resistance arteries from the rat cremaster muscle. Inhibition of the cytochrome P-450 4A pathway of arachidonic acid metabolism under normoxia induces NO production by the endothelium. Hypoxia induces an NO-mediated dilation when cytochrome P-450 4A enzymes are partially inhibited.

scholarly journals Regulation of arachidonic acid metabolism by cytochrome P-450 in rabbit kidney

1986 ◽  
Vol 238 (1) ◽  
pp. 283-290 ◽  
Author(s):  
M L Schwartzman ◽  
N G Abraham ◽  
M A Carroll ◽  
R D Levere ◽  
J C McGiff
Keyword(s):  
Arachidonic Acid ◽  
Acid Metabolism ◽  
Arachidonic Acid Metabolism ◽  
Rabbit Kidney ◽  
Aryl Hydrocarbon Hydroxylase ◽  
Outer Medulla ◽  
Aryl Hydrocarbon ◽  
Arachidonic Acid Metabolites ◽  
Acid Metabolites ◽  
Cytochrome P 450

Renal microsomal cytochrome P-450-dependent arachidonic acid metabolism was correlated with the level of cytochrome P-450 in the rabbit kidney. Cobalt, an inducer of haem oxygenase, reduced cytochrome P-450 in both the cortex and medulla in association with a 2-fold decrease in aryl-hydrocarbon hydroxylase, an index of cytochrome P-450 activity, and a similar decrease in the formation of cytochrome P-450-dependent arachidonic acid metabolites by renal microsomes (microsomal fractions). Formation of the latter was absolutely dependent on NADPH addition and was prevented by SKF-525A, an inhibitor of cytochrome P-450-dependent enzymes. Arachidonate metabolites of cortical microsomes were identified by g.c.-m.s. as 20- and 19-hydroxyeicosatetraenoic acid, 11,12-epoxyeicosatrienoic acid and 11,12-dihydroxyeicosatrienoic acid. The profile of arachidonic acid metabolites was the same for the medullary microsomes. Induction of cytochrome P-450 by 3-methylcholanthrene and beta-naphthoflavone increased cytochrome P-450 content and aryl-hydrocarbon hydroxylase activity by 2-fold in the cortex and medulla, and this correlated with a 2-fold increase in arachidonic acid metabolites via the cytochrome P-450 pathway. These changes can also be demonstrated in cells isolated from the medullary segment of the thick ascending limb of the loop of Henle, which previously have been shown to metabolize arachidonic acid specifically via the cytochrome P-450-dependent pathway. The specific activity for the formation of arachidonic acid metabolites by this pathway is higher in the kidney than in the liver, the highest activity being in the outer medulla, namely 7.9 microgram as against 2.5 micrograms of arachidonic acid transformed/30 min per nmol of cytochrome P-450 for microsomes obtained from outer medulla and liver respectively. These findings are consistent with high levels of cytochrome P-450 isoenzyme(s), specific for arachidonic acid metabolism, primarily localized in the outer medulla.

Eicosanoids and heart disease

1989 ◽  
Vol 67 (8) ◽  
pp. 911-911
Author(s):  
Morris Karmazyn ◽  
Margaret P. Moffat
Keyword(s):  
Arachidonic Acid ◽  
Heart Disease ◽  
Acid Metabolism ◽  
Arachidonic Acid Metabolism ◽  
New Era ◽  
Biological Phenomena ◽  
Other Substances ◽  
The Many ◽  
Cytochrome P 450 ◽  
Heart Foundation

The discovery of prostaglandins over 5 decades ago heralded a new era in the study of mediators or factors involved in physiological and pathophysiological processes. Prostaglandins, however, do not represent the sole products derived from arachidonic acid or other fatty acid precursors; instead these fatty acids can undergo metabolism to numerous bioactive compounds derived from cyclooxygenase, lipoxygenase, as well as the recently discovered epoxygenase cytochrome P-450 dependent pathways. Collectively, these products are commonly referred to as eicosanoids and have been implicated in numerous biological phenomena. It has long been hypothesized that the prostaglandins play an important role in cardiovascular regulation. For instance, the concept of a balance between the vasoconstrictor, prothrombotic properties of some arachidonic acid derived products and the opposing actions of others led to the development of drug therapies against thromboembolic disorders. Aspirin, for example, a well-known cyclooxygenase inhibitor, has been shown to be efficacious against myocardial infarction and stroke of embolic origin. Moreover, cyclooxygenase- and lipoxygenase-derived products have been implicated in various types of cardiac dysfunction including coronary constriction, arrhythmogenesis, anaphylactic reactions, or ischemic and reperfusion injury.In view of the evolving complexity of arachidonic acid metabolism and increasing evidence that eicosanoids, either alone, or through interaction with other substances, represent important mediators in either the development of heart disease or the myocardial response to injury, we organized this symposium entitled Eicosanoids and Heart Disease concurrent with the 31st Annual Meeting of the Canadian Federation of Biological Societies. A one-half day symposium precludes the possibility of detailed coverage of the many areas in cardiovascular disease in which eicosanoid participation could be implicated and which ideally one would hope to cover. The organizers' aim was to address, in the form of research presentations or reviews, current areas of investigation dealing with selected topics in heart disease.The success of this symposium was made possible by the participation of several distinguished scientists. We would also like to thank the Pharmacological Society of Canada, the Canadian Heart Foundation, Upjohn Canada, Sterling Drug, and Ciba-Geigy U.S. A. for financial support. The organizers thank Dr. J. Burka for serving as Guest Editor and Mrs. L. Hendrickson of this Journal for coordinating the submission of the manuscripts.

scholarly journals Differences between SHR and WKY in Content of Cytochrome P-450 Isozymes Which Contribute Arachidonic Acid Metabolism

1991 ◽  
Vol 32 (4) ◽  
pp. 560-560
Author(s):  
Susumu Imaoka ◽  
Kazuo Takaori ◽  
Tokihito Yukimura ◽  
Kenjiro Yamamoto ◽  
Yoshihiko Funae
Keyword(s):  
Arachidonic Acid ◽  
Acid Metabolism ◽  
Arachidonic Acid Metabolism ◽  
Cytochrome P 450
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