A. Dendorfer et al., Pathways of bradykinin degradation in blood and plasma of normotensive andhypertensive rats, AM J P-HEAR, 280(5), 2001, pp. H2182-H2188
Citations number
38
Categorie Soggetti
Cardiovascular & Hematology Research
Journal title
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
Kinins are vasoactive peptide hormones that can confer protection against t
he development of hypertension. Because their efficacy is greatly influence
d by the rate of enzymatic degradation, the activities of various kininases
in plasma and blood of spontaneously hypertensive rats (SHR) were compared
with those in normotensive Wistar-Kyoto rats (WKY) to identify pathogenic
alterations. Either plasma or whole blood was incubated with bradykinin (10
muM). Bradykinin and kinin metabolites were measured by high-performance l
iquid chromatography. Kininase activities were determined by cumulative inh
ibition of angiotensin I-converting enzyme (ACE), carboxypeptidase N (CPN),
and aminopeptidase P (APP), using selective inhibitors. Plasma of WKY rats
degraded bradykinin at a rate of 13.3 +/- 0.94 mu mol . min(-1) . l(-1). T
he enzymes ACE, APP, and CPN represented 92% of this kininase activity, wit
h relative contributions of 52, 25, and 16%, respectively. Inclusion of blo
od cells at physiological concentrations did not extend the activities of t
hese plasma kininases further. No differences of kinin degradation were fou
nd between WKY and SHR. The identical conditions of kinin degradation in WK
Y and SHR suggest no pathogenic role of kininases in the SHR model of genet
ic hypertension.