A transgenic mouse model in which cytochrome P450 4F2 (CYP4F2) was expressed in multiple organs was expected to clarify the role of 20-hydroxyeicosatetraenoic acid (20-HETE) in the regulation of blood pressure, compared with our previously established kidney androgen-regulated protein (KAP) promoter CYP4F2 transgenic mouse model which predominantly showed renal overexpression of CYP4F2. A novel CYP4F2 transgenic mouse model driven by the cyto-megalovirus (CMV) promoter was generated and identified by PCR and subsequent sequencing. Extensive study of CMV-CYP4F2 transgenic mice demonstrated that CYP4F2 was exclusively expressed in the liver, while 20-HETE levels in the urine, kidney and blood were not affected, and there was no resulting change in the systolic blood pressure. This was in contrast to KAP-CYP4F2 transgenic mice which exerted prohypertensive action of 20-HETE resulting from the renal overexpression of CYP4F2. In addition, CYP4F2 overwhelmed the endogenous renal Cyp4a family mRNA levels in the KAP-CYP4F2 but not in the CMV-CYP4F2 transgenic mice. These results support the idea that overexpression of renal CYP4F2, leading to high 20-HETE in the urine and blood, may account for the elevated blood pressure. The CMV promoter did not direct CYP4F2 expression into extensive tissues and organs in an attempt to clarify the action of 20-HETE.