Characterization of angiotensin converting enzyme in isolated cerebral microvessels from spontaneously hypertensive and normotensive rats.
OBJECTIVE
Abnormalities in the vascular renin-angiotensin system have been hypothesized to contribute to the pathogenesis and complications of hypertension. In animal models of hypertension, there is wide variation in reported vascular angiotensin converting activity, particularly in cerebral microvessels. In this study, we sought to characterize, quantitate and compare cerebral microvessel angiotensin converting enzyme (ACE) in genetically hypertensive rats and normotensive rats.


METHODS
Brain microvascular ACE from 14-week-old spontaneously hypertensive rats (SHR) was measured and compared with ACE from brain microvessels of normotensive Wistar-Kyoto (WKY) controls.


METHODS
Isolated cerebral microvascular ACE was measured using two methods, enzyme kinetic assay or radioligand binding assay.


RESULTS
In SHR, cerebral microvessel ACE was of similar activity and concentration and had similar ligand binding affinities to WKY rats. Plasma ACE activity was significantly elevated in WKY rats compared with SHR.


CONCLUSIONS
Cerebral microvascular ACE is similar in SHR and WKY rats. Microvascular ACE is unlikely to participate in the pathogenesis or complications of hypertension in this model.
Perich
R
R
Department of Medicine, University of Melbourne, Austin Hospital, Heidelberg, Victoria, Australia.
Jackson
B
B
Paxton
D
D
Johnston
C I
CI
D000818:Animals; D001921:Brain / Q000098:blood supply / Q000201:enzymology*; D006973:Hypertension / Q000201:enzymology* / Q000235:genetics; D008297:Male; D008833:Microcirculation / Q000201:enzymology; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism*; D011869:Radioligand Assay; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
D007703:Peptidyl-Dipeptidase A