Chronic ACE inhibitor treatment increases angiotensin type 1 receptor binding in vivo in the dog kidney.
OBJECTIVE
PET imaging has been recently introduced for investigating the type 1 angiotensin II receptor (AT(1)R) in vivo. The goal of the present study was to investigate the effects of acute and chronic exposure to angiotensin converting enzyme inhibitors (ACEI) on the AT(1)R in the dog kidney.


METHODS
Animals were imaged at baseline, after acute intravenous ACEI treatment and after a chronic 2-week exposure to an oral ACEI. Control animals were imaged at identical time points in the absence of ACEI treatment.


RESULTS
In vivo AT(1)R binding expressed by K (i) was increased in the renal cortex by chronic ACEI treatment (p < 0.05). In vitro measurements of AT(1)R density (B (max)) also revealed significant increases in AT(1)R in isolated glomeruli (p < 0.05). Plasma renin activity was increased, but angiotensin II (Ang II) and the Ang II/Ang I ratio showed a weak correlation with chronic ACEI treatment, consistent with an Ang II escape phenomenon.


CONCLUSIONS
This study reveals, for the first time, that chronic ACEI treatment increases AT(1)R binding in vivo in the dog renal cortex.
Zober
Tamas G
TG
Department of Radiology and Surgery, Johns Hopkins University, Baltimore, MD, USA.
Fabucci
Maria Elena
ME
Zheng
Wei
W
Brown
Phillip R
PR
Seckin
Esen
E
Mathews
William B
WB
Sandberg
Kathryn
K
Szabo
Zsolt
Z
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage*; D000818:Animals; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D007668:Kidney / Q000000981:diagnostic imaging* / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D011485:Protein Binding / Q000187:drug effects; D011877:Radionuclide Imaging; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism*
D000806:Angiotensin-Converting Enzyme Inhibitors; D044140:Receptor, Angiotensin, Type 1