Determination of aminopeptidase X activity in tissues of normo- and hypertensive rats by capillary electrophoresis.
Aminopeptidase X, an enzyme that degrades angiotensin I to des-asp-angiotensin I, was determined in the lung, liver, kidney, plasma, endothelium and aortic smooth muscle of the spontaneously hypertensive rat (SHR) and its normotensive control, the Wistar Kyoto rat (WKY). The enzyme activity in the lung, kidney, plasma and endothelium of the SHR was elevated and this supports an earlier suggestion that in certain critical tissues of the SHR, the degradation of angiotensin I is shunted in favour of the des-asp-angiotensin I pathway. In these tissues, the formation of pressor angiotensin II would be curtailed and that of des-asp-angiotensin I enhanced. As des-asp-angiotensin I lacks direct vasopressor action, its preferential formation over that of angiotensin II could be a physiological response to the prevailing hypertension in the SHR.
Sim
M K
MK
Department of Pharmacology, Faculty of Medicine, National University of Singapore, Singapore.
Lim
B C
BC
D000626:Aminopeptidases / Q000097:blood / Q000378:metabolism*; D000818:Animals; D019075:Electrophoresis, Capillary; D004730:Endothelium, Vascular / Q000201:enzymology; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D008168:Lung / Q000201:enzymology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000201:enzymology; D009928:Organ Specificity; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
D000626:Aminopeptidases; C109065:aminopeptidase X