1. Losartan, a specific angiotensin II receptor antagonist, increases angiotensin I and angiotensin II release from isolated rat hind legs: Evidence for locally regulated renin-angiotensin system in vascular tissue
- Author
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Makio Tani, Hironobu Sanada, Shigeatsu Hashimoto, Kenji Mizuno, Makoto Ohtsuki, Soitsu Fukuchi, Hidetsuna Watanabe, Susumu Niimura, and Hiroshi Haga
- Subjects
Male ,medicine.medical_specialty ,Time Factors ,Tetrazoles ,Angiotensin II receptor antagonist ,Hindlimb ,Nephrectomy ,Losartan ,Muscle, Smooth, Vascular ,General Biochemistry, Genetics and Molecular Biology ,Renin-Angiotensin System ,Angiotensin Receptor Antagonists ,Internal medicine ,Renin–angiotensin system ,medicine ,Animals ,General Pharmacology, Toxicology and Pharmaceutics ,Chemistry ,Angiotensin II ,Biphenyl Compounds ,Imidazoles ,General Medicine ,Rats ,Perfusion ,Biphenyl compound ,Endocrinology ,medicine.anatomical_structure ,cardiovascular system ,Blood Vessels ,Angiotensin I ,hormones, hormone substitutes, and hormone antagonists ,medicine.drug ,Blood vessel - Abstract
The effect of Losartan (10(-9) to 10(-6) M) on angiotensins I and II release was examined in isolated hind legs perfused with Krebs-Ringer solution from normal and bilaterally nephrectomized rats. Losartan increased dramatically both angiotensins I (Ang I) and II (Ang II) release in a dose-dependent fashion; the maximal percent increment in Ang I and Ang II release evoked by Losartan (10(-6) M) was about +380% and +160%, respectively, in normal rat hind legs. In nephrectomized animals, Losartan elicited a marked increase in both peptides dose-dependently. There was a highly positive correlation between the released amounts of Ang I and that of Ang II altered by Losartan in either normal (r = 0.954) or nephrectomized rats (r = 0.923). These results not only confirm the existence of a functional renin-angiotensin system in vascular tissues, but also suggest that the system is regulated by locally generated Ang II.
- Published
- 1992