Plasma renin activity and angiotensin I and aldosterone concentrations in cats with hypertension associated with chronic renal disease.
OBJECTIVE
To determine plasma renin activity (PRA), angiotensin I (Ang I), and aldosterone (ALDO) values in clinically normal cats and hypertensive cats with renal disease, and the relation of renin-angiotensin-aldosterone activation in response to treatment with beta-blockers or angiotensin-converting enzyme inhibitors.


METHODS
5 normotensive healthy control cats and 12 Untreated hypertensive cats with chronic renal disease.


METHODS
Untreated hypertensive cats received either propanolol (n = 6) or enalapril (n = 6) as initial antihypertensive treatment. PRA and baseline plasma Ang I and ALDO concentrations were measured prior to treatment. The difference in Ang I values at 2 hours (Ang I generated) and at time 0 (baseline Ang I) was divided by 2 to give the PRA value. Values for PRA, Ang I, and ALDO were obtained from 5 clinically normal, normotensive cats, and compared with those of hypertensive cats.


RESULTS
Mean +/- SD PRA and baseline Ang I concentration were not significantly different between normotensive and hypertensive cats. Mean ALDO concentration was significantly (P = 0.0235) higher in hypertensive cats with renal disease (186.18 +/- 145.15 pg/ml), compared with that in normotensive controls (51.1 +/- 16.76 pg/ml). Eight hypertensive cats with ALDO concentration > 2 SD above the mean concentration in control cats had low (n = 3), normal (n = 4), or high (n = 1) PRA, suggesting variable activation of the renin-angiotensin-aldosterone axis in the hypertensive state. Overall, enalapril was effective long-term monotherapy in only 1 of 6 cats, and propranolol was ineffective as long-term monotherapy.


CONCLUSIONS
Evaluation of the renin-angiotensin-aldosterone system in cats with hypertension associated with renal disease may lead to greater understanding of the pathophysiologic mechanisms of this disorder. In addition, identification of biochemical markers in hypertensive cats may permit selection of appropriate antihypertensive drugs. Propranolol and enalapril were ineffective antihypertensive agents in most cats of this study.
Jensen
J
J
Department of Medical Sciences, University of Wisconsin-Madison 53706, USA.
Henik
R A
RA
Brownfield
M
M
Armstrong
J
J
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology / Q000627:therapeutic use; D000450:Aldosterone / Q000097:blood*; D000804:Angiotensin II / Q000097:blood*; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002371:Cat Diseases / Q000097:blood* / Q000188:drug therapy / Q000209:etiology; D002415:Cats; D004305:Dose-Response Relationship, Drug; D004656:Enalapril / Q000494:pharmacology / Q000627:therapeutic use; D005260:Female; D006977:Hypertension, Renal / Q000097:blood / Q000209:etiology / Q000662:veterinary*; D007676:Kidney Failure, Chronic / Q000097:blood / Q000150:complications / Q000662:veterinary*; D008297:Male; D011433:Propranolol / Q000494:pharmacology / Q000627:therapeutic use; D011863:Radioimmunoassay / Q000379:methods / Q000662:veterinary; D012083:Renin / Q000097:blood*; D012084:Renin-Angiotensin System / Q000187:drug effects / Q000502:physiology
D000319:Adrenergic beta-Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D000804:Angiotensin II; D000450:Aldosterone; D004656:Enalapril; D011433:Propranolol; D012083:Renin