High affinity binding sites for Perindopril a new inhibitor of angiotensin-I-converting enzyme (ACE) in the rabbit kidney: possible evidence for localization of ACE in endothelial structures and in glomerular mesangium.
The tissue distribution of Perindopril, a new potent inhibitor of the angiotensin-converting enzyme (ACE), was studied after in vivo intravenous injection into rabbits of tracer amounts of the tritiated drug either alone (no modification of the renin angiotensin system) or along with a pharmacologic dose of 10 mg/kg unlabelled Perindopril. Lung and kidneys were the most densely labelled tissues. Kidney distribution of tritiated Perindopril was studied either by histo-autoradiography or by measurement of radioactivity in the homogenates of dissected kidney zones. A close parallelism was found between the distribution patterns of ACE and radioactivity throughout the kidney. Tritiated-Perindopril binding was inhibited by concurrent treatment of the animals with the unlabelled drug or pretreatment with Captopril. Autoradiographic study of kidney slices after the administration of tracer amounts of Perindopril showed an intense labelling of the glomerular mesangium and of endothelial structures of blood vessels, and a lack of labelling of tubular epithelial cells. The possible occurrence of two pools of "ACE-like" activity in the kidney is discussed, namely i) one pool which is labelled by tritiated Perindopril, located in glomerular mesangium and endothelial structures which may be involved in the pharmacological action of ACE inhibitors; and ii) a second pool located in the proximal-tubule cell brush-border, remaining unlabelled by Perindopril, for which the high amount of neutral endopeptidase present at this site may be responsible.
Morin
J P
JP
Institute National de la Santé et de la Recherche Médicale, I.N.S.E.R.M. U-295, University of Rouen, France.
Moulin
B
B
Borghi
H
H
Fillastre
J P
JP
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000378:metabolism / Q000493:pharmacokinetics*; D000818:Animals; D001345:Autoradiography; D002216:Captopril / Q000494:pharmacology; D002855:Chromatography, Thin Layer; D004730:Endothelium, Vascular / Q000378:metabolism*; D005260:Female; D005920:Glomerular Mesangium / Q000378:metabolism*; D007211:Indoles / Q000378:metabolism / Q000493:pharmacokinetics*; D007668:Kidney / Q000378:metabolism*; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism; D020913:Perindopril; D011817:Rabbits; D011955:Receptors, Drug / Q000378:metabolism*; D014018:Tissue Distribution
D000806:Angiotensin-Converting Enzyme Inhibitors; D007211:Indoles; D011955:Receptors, Drug; D002216:Captopril; D007703:Peptidyl-Dipeptidase A; D020913:Perindopril