Targeted disruption of soluble epoxide hydrolase reveals a role in blood pressure regulation

Renal microsomal cytochrome P-450 monooxygenase-dependent metabolism of ara chidonic acid generates a series of regioisomeric epoxyeicosatrienoic acids that can be further metabolized by soluble epoxide hydrolase to the corres ponding dihydroxyeicosatrienoic acids. Evidence exists that these metabolit es affect renal function and, in particular, blood pressure regulation. To examine this possibility, blood pressure and renal arachidonic acid metabol ism 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 pr esence of dietary salt loading. Both female soluble epoxide hydrolase-null and wild-type female mice also had significantly lower systolic blood press ure than male wild-type mice. Renal formation of epoxyeicosatrienoic and di hydroxyeicosatrienoic acids was markedly lower for soluble epoxide hydrolas e-null versus wild-type mice of both sexes. Although disruption of soluble epoxide hydrolase in female mice had minimal effects on blood pressure, del etion of this gene feminized male mice by lowering systolic blood pressure and altering arachidonic acid metabolism. These data provide the first dire ct evidence for a role for soluble epoxide hydrolase in blood pressure regu lation and identify this enzyme as a novel and attractive target for therap eutic intervention in hypertension.