Related Experiment Video
Updated: May 22, 2025
Transdermal Measurement of Glomerular Filtration Rate in Mice
Published on: October 21, 2018
Correlation of Urine Ammonia Excretion With Renal Function in Healthy Cats and Cats With Kidney Disease
Eleanor E Brown1, Kirsten L Cooke2, Rebeca A Castro2,3
1Austin Veterinary Emergency and Specialty, Austin, Texas, USA.
Background:
Inadequate ammonia excretion is thought to drive the development of metabolic acidosis in people with CKD and to correlate with worse outcomes.
Objectives:
To determine if urine ammonia-to-creatinine ratio (UACR) correlates with serum creatinine as a renal function marker in healthy cats and cats with CKD and whether UACR is related to the presence of CKD.
Animals:
The study group comprised 74 healthy and 45 stable IRIS stage 2-4 CKD cats.
Methods:
Prospective, single-time point study. Serum biochemistry variables were measured. Urinary ammonia and creatinine concentrations were measured and used to calculate UACR. Group comparisons were made using the Mann-Whitney test. Correlation between UACR concentrations and serum renal and electrolyte values used Spearman's correlation test. Relationships between UACR, renal variables, electrolytes, urine specific gravity, age, and body weight were explored with multiple linear regression.
Results:
Chronic kidney disease cats (median 4.2; range 0.6-9.2) had lower UACR than healthy cats (median 7.6; range 3.0-23.7; p < 0.01). UACR was inversely correlated with creatinine concentration (p < 0.01, rs = -0.545). The relationship between UACR and creatinine persisted after controlling for age, body weight, electrolytes, renal functional variables, and urine-specific gravity.
Conclusions And Clinical Importance:
These findings suggest that ammonia excretion is impaired with declining renal function.
Related Concept Videos
01:17Factors Affecting Renal Clearance: Renal Impairment
One condition associated with renal failure is uremia. Uremia is characterized by impaired glomerular filtration and fluid accumulation in the body. This condition hinders the renal clearance of drugs, resulting in drug accumulation and potential...
01:24Physiology of Urine Formation
Glomerular Filtration
The first stage in urine formation is glomerular filtration. Each kidney contains approximately 1 million nephrons, the functional units of filtration, with a...
01:10Nephrons
01:20Renal Corpuscle
Glomerulus: Structure and Function
The glomerulus is a tiny, intricate network of capillaries located at the beginning of the nephron. It's enveloped by the Bowman's capsule and receives its blood supply from an afferent arteriole, which divides into numerous...
01:13Introduction to Urinary System
The kidneys are bean-shaped organs located in the retroperitoneal space, on either side of the vertebral column, between the T12 and L3 vertebrae. They are partially protected by the rib cage and surrounded by perirenal fat, which provides cushioning. They are responsible for urine formation and play critical roles in regulating blood pressure, electrolyte levels, and hormone production. The ureters...
01:11One-Compartment Open Model: Urinary Excretion Data and Determination of k