Soluble epoxide hydrolase contamination of specific catalase preparations inhibits epoxyeicosatrienoic acid vasodilation of rat renal arterioles

Kathryn M. Gauthier, Lauren Olson, Adam Harder, Marilyn Isbell, John D. Imig, David D. Gutterman, J R Falck, William B. Campbell

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

Cytochrome P-450 metabolites of arachidonic acid, the epoxyeicosatrienoic acids (EETs) and hydrogen peroxide (H 2O 2), are important signaling molecules in the kidney. In renal arteries, EETs cause vasodilation whereas H 2O 2 causes vasoconstriction. To determine the physiological contribution of H 2O 2, catalase is used to inactivate H 2O 2. However, the consequence of catalase action on EET vascular activity has not been determined. In rat renal afferent arterioles, 14,15-EET caused concentrationrelated dilations that were inhibited by Sigma bovine liver (SBL) catalase (1,000 U/ml) but not Calbiochem bovine liver (CBL) catalase (1,000 U/ml). SBL catalase inhibition was reversed by the soluble epoxide hydrolase (sEH) inhibitor tAUCB (1 μM). In 14,15-EET incubations, SBL catalase caused a concentration-related increase in a polar metabolite. Using mass spectrometry, the metabolite was identified as 14,15-dihydroxyeicosatrienoic acid (14,15-DHET), the inactive sEH metabolite. 14,15-EET hydrolysis was not altered by the catalase inhibitor 3-amino-1,2,4-triazole (3-ATZ; 10-50 μM), but was abolished by the sEH inhibitor BIRD-0826 (1-10 μM). SBL catalase EET hydrolysis showed a regioisomer preference with greatest hydrolysis of 14,15-EET followed by 11,12-, 8,9- and 5,6-EET (V max = 0.54 ± 0.07, 0.23 ± 0.06, 0.18 ± 0.01 and 0.08 ± 0.02 ng DHET·U catalase -1 ·min -1, respectively). Of five different catalase preparations assayed, EET hydrolysis was observed with two Sigma liver catalases. These preparations had low specific catalase activity and positive sEH expression. Mass spectrometric analysis of the SBL catalase identified peptide fragments matching bovine sEH. Collectively, these data indicate that catalase does not affect EET-mediated dilation of renal arterioles. However, some commercial catalase preparations are contaminated with sEH, and these contaminated preparations diminish the biological activity of H 2O 2 and EETs.

Original languageEnglish (US)
Pages (from-to)F765-F772
JournalAmerican Journal of Physiology - Renal Physiology
Volume301
Issue number4
DOIs
StatePublished - Oct 2011

Keywords

  • Arteries
  • EDHF
  • Epoxyeicosatrienoic acids
  • Hydrogen peroxide

ASJC Scopus subject areas

  • Physiology
  • Urology

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