This study was conducted to test the hypothesis that the CYP1B1 (cytochrome P450 1B1)-testosterone metabolite 6β-hydroxytestosterone contributes to angiotensin II-induced hypertension by promoting activation of group IV cPLA
2
α (cytosolic phospholipase A
2
α) and generation of prohypertensive eicosanoids in male mice. Eight-week-old male intact or orchidectomized
cPLA
2
α
+/+
/
Cyp1b1
+/+
and
cPLA
2
α
–/–
/
Cyp1b1
+/+
and intact
cPLA
2
α
+/+
/
Cyp1b1
–/–
mice were infused with angiotensin II (700 ng/kg/min, subcutaneous) for 2 weeks and injected with 6β-hydroxytestosterone (15 μg/g/every third day, intraperitoneal). Systolic blood pressure was measured by tail-cuff and confirmed by radiotelemetry. Angiotensin II-induced increase in systolic blood pressure, cardiac and renal collagen deposition, and reactive oxygen species production were reduced by disruption of the
cPLA
2
α
or
Cyp1b1
genes or by administration of the arachidonic acid metabolism inhibitor 5,8,11,14-eicosatetraynoic acid to
cPLA
2
α
+/+
/
Cyp1b1
+/+
mice. 6β-hydroxytestosterone treatment restored these effects of angiotensin II in
cPLA
2
α
+/+
/
Cyp1b1
–/–
mice but not in orchidectomized
cPLA
2
α
–/–
/
Cyp1b1
+/+
mice, which were lowered by 5,8,11,14-eicosatetraynoic acid in
cPLA
2
α
+/+
/
Cyp1b1
–/–
mice. Antagonists of prostaglandin E
2
-EP1/EP3 receptors and thromboxane A
2
-TP receptors decreased the effect of 6β-hydroxytestosterone in restoring the angiotensin II-induced increase in systolic blood pressure, cardiac and renal collagen deposition, and reactive oxygen species production in
cPLA
2
α
+/+
/
Cyp1b1
–/–
mice. These data suggest that 6β-hydroxytestosterone promotes angiotensin II-induced increase in systolic blood pressure and associated pathogenesis via cPLA
2
α activation and generation of eicosanoids, most likely prostaglandin E
2
and thromboxane A
2
that exerts prohypertensive effects by stimulating EP1/EP3 and TP receptors, respectively. Therefore, agents that selectively block these receptors could be useful in treating testosterone exacerbated angiotensin II-induced hypertension and its pathogenesis.