Urinary protein analysis in cardiomyopathy-affected and healthy cattle by SDS-polyacrylamide gel electrophoresis

Urinary proteins of cardiomyopathy (CMP)-affected (n = 31) and of healthy cattle (n = 35) were analyzed by a combination of SDS-polyacrylamide gel electrophoresis and silver stain. The following results were obtained: 1) Out of the various urinary proteins found in CMP-affected and healthy cattle, IgG, Tf, Alb, alpha 1-acid GP, Apo A1, IgG heavy and light chain could be identified. 2) In CMP-affected cattle, all the proteins mentioned above were detected in increased amounts in the urine. The quantities of Alb, Tf, and IgG were especially large. 3) In the case of CMP, the permeability of the glomerular filter was highly increased for large serum proteins. The tubular protein reabsorption of small proteins was less altered by the disease. 4) Although the electrophoretic pattern of the urinary proteins was abnormal in all the examined CMP-affected animals, the urinary protein concentrations were increased (> 230 mg/l) in only 42% of the cases. Consequently, the urinary protein concentration is not a reliable parameter for detecting renal diseases. 5) For both CMP-affected and healthy cattle the urinary protein pattern depended neither on the urine sampling technique (catheterization, spontaneous urine) nor on the reproductive stage.