Related Experiment Video
Updated: Jul 16, 2026

Fecal Glucocorticoid Analysis: Non-invasive Adrenal Monitoring in Equids
Published on: April 25, 2016
Measurement of aldosterone in feline, canine and human urine
H M Syme1, M G R Fletcher, S R Bailey
1Department of Veterinary Clinical Sciences, The Royal Veterinary College, University of London, Royal College Street, London NW1 0TU.
Background:
Systemic hypertension is an important problem in older cats associated with kidney disease and hypokalaemia, suggesting that excessive activity of the renin-angiotensin-aldosterone system might contribute to the hypertensive state. Fluctuations in plasma renin activity and plasma aldosterone concentrations complicate the interpretation of these assays.
Objectives:
The aim of this study was to determine whether measurement of urinary aldosterone excretion in cats aided the investigation of hypertension.
Methods:
Urine concentrations of free (ethyl acetate extract) and 18-glucuronidated aldosterone (acid hydrolysis before extraction) were measured by radioimmunoassay in normal, normotensive and hypertensive azotaemic cats (n=11 per group). Urine samples from 11 healthy human volunteers and eight normal dogs were also analysed for comparison. Urinary aldosterone concentration was corrected for the urinary creatinine concentration.
Results:
Cats excreted 7.3 times less free aldosterone than human beings, and no free aldosterone was detected in dog urine. Acid hydrolysis led to large increases in aldosterone recovery from both human beings and dog but not feline urine. No significant effect of hypertension or azotaemia on feline urinary aldosterone concentration was found.
Clinical Significance:
Measurement of aldosterone in feline urine using the available methodology has limited or no utility in investigating feline hypertension.
Related Concept Videos
Urine Studies I: Urinalysis
Regulation of Sodium and Potassium
Sodium Regulation
Sodium ions make up approximately 90% of extracellular cations, with a normal blood plasma concentration of 136–148 mEq/L. A decrease in blood volume and pressure triggers the release of renin from granular cells in the juxtaglomerular complex (JGC), primarily in...
Physiology of the Genitourinary System III: Urine Concentration and Dilution
Serum Studies: Renal Function Tests

