Characterization of the intrarenal renin‐angiotensin system in cats with naturally occurring chronic kidney disease

Background The role of the renin‐angiotensin‐aldosterone system in cats with chronic kidney disease (CKD) is incompletely understood. Objective To characterize components of the intrarenal renin‐angiotensin system (RAS) in cats with CKD. Animals Eleven cats with naturally occurring CKD (CKD group) and 8 healthy control cats. Methods Renal tissue samples were evaluated by reverse‐transcription polymerase chain reaction for renin, angiotensinogen, angiotensin‐converting enzyme (ACE), and angiotensin II type 1 receptor transcript levels, and by liquid chromatography‐mass spectrometry for quantification of angiotensin I, II, III, and IV concentrations. Linear mixed models were used to compare gene transcript levels and concentrations of angiotensin peptides between groups. Results Cats of the CKD group were significantly older (P