title: Hypertension and angiotensin II hypersensitivity in aminopeptidase A-deficient mice.
abstract: Local concentrations of the vasopressor peptide, angiotensin II (AngII), depend upon the balance between synthesis and degradation. Previous studies of blood pressure (BP) regulation have focused primarily on the generation of AngII and its receptors, and less attention has been devoted to angiotensin degradation. Aminopeptidase A (APA, EC 3.4.11.7) is responsible for the N-terminal cleavage of AngII, a hydrolytic event that serves as a rate-limiting step in angiotensin degradation. To evaluate the physiological role of APA, we examined BP homeostasis in APA-deficient mice. We measured basal BP and BP with continuous infusion of AngII in APA mutant mice by tail-cuff method. We also evaluated the development and histology of AngII-targeted organs as well as urine excretion in these mice. Homozygous APA mutant mice were found to have elevated basal systolic BP when compared with heterozygous mutant and wild-type littermate mice. Infusion of AngII led to an enhanced systolic BP response in the APA-deficient mice. Despite the sustained elevation of BP in APA knockout mice, neither their renal and cardiac sizes nor their histological appearances were not different from control mice. Moreover, the volume, osmolality, and electrolyte content of the urine were normal in APA-deficient mice. APA deficiency increased baseline BP and enhanced the hypertensive response to increased levels of AngII. These findings indicate a physiological role for APA in lowering BP and offer novel insight into the mechanisms for developing hypertension.
authors.affiliation: Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Mitsui
authors.forename: Seiji
authors.initials: S
authors.lastname: Nomura
authors.forename: Mayumi
authors.initials: M
authors.lastname: Okada
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Ohno
authors.forename: Honami
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Nakashima
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Murata
authors.forename: Mikihito
authors.initials: M
authors.lastname: Takeuchi
authors.forename: Naohiko
authors.initials: N
authors.lastname: Kuno
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Nagasaka
authors.forename: Jiyang
authors.initials: J
authors.lastname: O-Wang
authors.forename: Max D
authors.initials: MD
authors.lastname: Cooper
authors.forename: Shigehiko
authors.initials: S
authors.lastname: Mizutani
mesh_terms: D000626:Aminopeptidases / Q000172:deficiency / Q000502:physiology*; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D004342:Drug Hypersensitivity / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D043384:Glutamyl Aminopeptidase; D006321:Heart / Q000502:physiology; D006706:Homeostasis / Q000502:physiology; D006720:Homozygote; D006973:Hypertension / Q000139:chemically induced / Q000378:metabolism / Q000503:physiopathology*; D007668:Kidney / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D014662:Vasoconstrictor Agents
chemical_list: D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D000626:Aminopeptidases; D043384:Glutamyl Aminopeptidase