Spectrophotometric assay for mammalian cytosolic epoxide hydrolase using trans-stilbene oxide as the substrate

Hasegawa, L.; Hammock, Bruce D.

doi:10.1016/0006-2952(82)90408-7

Cited by 34 publications

(13 citation statements)

References 22 publications

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“…Analysis of sEH-dependent Metabolism-Cytosolic trans-stilbene oxide hydration was determined spectrophotometrically essentially as described previously (28). For analyses of AA metabolism, tissue S-9 fraction (1 mg) was incubated with 20 M AA containing 0.5 Ci of 1-[ 14 C]AA at 37°C in 0.1 M potassium phosphate buffer, pH 7.4, in a final volume of 1 ml.…”

Section: Methodsmentioning

confidence: 99%

Targeted Disruption of Soluble Epoxide Hydrolase Reveals a Role in Blood Pressure Regulation

Sinal¹,

Miyata²,

Tohkin³

et al. 2000

Journal of Biological Chemistry

316

270

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Renal microsomal cytochrome P-450 monooxygenasedependent metabolism of arachidonic acid generates a series of regioisomeric epoxyeicosatrienoic acids that can be further metabolized by soluble epoxide hydrolase to the corresponding dihydroxyeicosatrienoic acids. Evidence exists that these metabolites affect renal function and, in particular, blood pressure regulation. To examine this possibility, blood pressure and renal arachidonic acid metabolism were examined in mice with a targeted disruption of the soluble epoxide hydrolase gene. Systolic blood pressure of male soluble epoxide hydrolase-null mice was lower compared with wild-type mice in both the absence and presence of dietary salt loading. Both female soluble epoxide hydrolase-null and wild-type female mice also had significantly lower systolic blood pressure than male wild-type mice. Renal formation of epoxyeicosatrienoic and dihydroxyeicosatrienoic acids was markedly lower for soluble epoxide hydrolase-null versus wild-type mice of both sexes. Although disruption of soluble epoxide hydrolase in female mice had minimal effects on blood pressure, deletion of this gene feminized male mice by lowering systolic blood pressure and altering arachidonic acid metabolism. These data provide the first direct evidence for a role for soluble epoxide hydrolase in blood pressure regulation and identify this enzyme as a novel and attractive target for therapeutic intervention in hypertension. Mammalian soluble epoxide hydrolase (sEH)1 is a cytosolic enzyme expressed in multiple tissues that catalyzes the conversion of a diverse group of epoxides to their corresponding diols (1, 2). The broad spectrum of xenobiotic epoxides metabolized by this enzyme suggests a role in the protection of cells against the potentially harmful effects of these compounds (3). However, sEH hydrates fatty acid epoxides most effectively, with epoxides of arachidonic acid (AA) being among the best substrates (4 -6). This metabolism may result in the formation of metabolites with greater or less biological activity, indicating that sEH may have important physiological functions. Intracellular metabolism of AA by prostaglandin H2 synthase, lipoxygenases, and the cytochrome P-450 (CYP) monooxygenase system generates a number of metabolites, collectively termed eicosanoids, with important biological and cell signaling roles (7-12). CYP-dependent metabolism of AA (Fig. 1) generates three primary classes of metabolites: mid-chain cis-trans-conjugated dienols (5-, 8-, 9-, 11-, 12-and 15-hydroxyeicosatetraenoic acids (HETEs)); -terminal alcohols (16-through 20-hydroxyeicosatetraenoic acids); and, cis-epoxyeicosatrienoic acids (6-, 8,9-, 11,12-, and 14,15 epoxyeicosatrienoic acids (EETs)) (13). EETs have been shown in vitro to be efficiently hydrated to their corresponding dihydroxyeicosatrienoic acids (DHETs) by sEH (5).Evidence exists for a variety of renal functions attributable to EETs and DHETs generated by CYP-dependent epoxygenase activity and sEH, respectively. Most notably, evidence exists for ...

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Section: Methodsmentioning

confidence: 99%

Targeted Disruption of Soluble Epoxide Hydrolase Reveals a Role in Blood Pressure Regulation

Sinal¹,

Miyata²,

Tohkin³

et al. 2000

Journal of Biological Chemistry

316

270

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“…Enzyme assay conditions were chosen on the basis of incubation time and protein concentration in other species studied in our laboratory. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] Naphthalene monooxygenase activity was determined by quantitation of naphthalene conjugate formation (Table 1). 7 Naphthalene incubations were prepared on ice in a final volume of 2 ml in 0.1 M phosphate buffer, pH 7.4.…”

mentioning

confidence: 99%

Hepatic and pulmonary enzyme activities in horses

Lakritz¹,

Winder²,

Noorouz-Zadeh³

et al. 2000

ajvr

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“…Other .epoxides such as trans-methyl styrene oxide and ally1 benzene oxide (26), ethylene oxide (27) and trans-stilbene oxide (28) are preferentially hydrated by the cytosolic hydrolase. It would be of interest to determine if such epoxides have an intracellular distribution pattern similar to that of styrene oxide.…”

Section: Discussionmentioning

confidence: 99%

Subcellular Distribution of Styrene Oxide in Rat Liver

1984

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The subcellular distribution of ('H)-styrene-7,8-oxide was studied in the rat liver. The compound was added to liver homogenate to give a final concentration of 2 x lo-'; 2 x lo-' and 2 x lo-' M. Subcellular fractions were obtained by differential centrifugation. Most of styrene oxide (59-88%) was associated with the cytosolic fraction. Less than 15 percent of the compound was retrieved in each of the nuclear, mitochondria1 and microsomal fractions. A considerable percentage of radioactivity was found unextractable with the organic solvents, suggesting that styrene oxide reacted with the endogenous compounds. The intracellular distribution of this epoxide was also studied in the perfused rat liver. Comparable results with those previously described were obtained. The binding of styrene oxide to the cytosolic protein was investigated by equilibrium dialysis and ultrafiltration. Only a small percentage of the compound was bound to protein.

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Spectrophotometric assay for mammalian cytosolic epoxide hydrolase using trans-stilbene oxide as the substrate

Cited by 34 publications

References 22 publications

Targeted Disruption of Soluble Epoxide Hydrolase Reveals a Role in Blood Pressure Regulation

Targeted Disruption of Soluble Epoxide Hydrolase Reveals a Role in Blood Pressure Regulation

Hepatic and pulmonary enzyme activities in horses

Subcellular Distribution of Styrene Oxide in Rat Liver

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