Evaluation of albminuria and electrophoresis of urinary proteins from dogs with hyperadrenocorticism and relation with systemic arterial pressure

Hyperadrenocorticism is one of the commonest endocrinopathies in dogs, and it is characterized by the excessive exposure of glucocorticoids excreted by adrenals. Chronic hypercortisolemia may promote several complications, including systemic hypertension and glomerulonephritis. Glomerulonephritis may initiate several variable degrees of proteinuria and leading to the development of chronic kidney disease. The loss of proteins through urine, mainly predominant albumin, is a characteristic of glomerular diseases and the determination of laboratorial variables, such as the urinary protein-to-creatinine ratio (UPC), urinary albumin-to- creatinine ratio (UAC; ELISA test) and electrophoresis of urinary proteins are recommended to elucidate the diagnosis. Therefore, the goal of this study is to evaluate the relationship between proteinuria and systemic arterial hypertension in dogs with hyperadrenocorticism and to determine through evaluation of albuminuria and molecular weight of urinary proteins, the segment of the nephron that could be damaged. Thirty dogs with hyperadrenocorticism were evaluated and subdivided into groups; 13 dogs with systemic arterial hypertension (group I) and 17 normotensive (group II). The UPC was determined, as well as UAC and the urine protein electrophoresis by polyacrylamide gel technique, containing dodecyl sodium sulphate (SDS-PAGE). The results were compared with data obtained from 30 clinically healthy dogs. No association between systemic arterial hypertension and albuminuria was detected in dogs with hyperadrenocorticism as well as no alterations of proteins patterns or molecular weights bands of low (<60 kDa) or high molecular weight (>60 kDa) was found. However, dogs with hyperadrenocorticism may develop glomerular and tubular injuries that were characterized by the presence of albuminuria and proteins of low and high molecular weights, independently of systemic arterial hypertension. In conclusion, the quantitative (UPC and UAC) and qualitative (SDS-PAGE) evaluation of urinary proteins could add information to indicate the possible segments of the nephrons that caused the loss of those proteins.