Urinary gamma-glutamyl transferase and the degree of renal dysfunction in 75 bitches with pyometra

In 75 bitches with pyometra single urine samples were examined for gamma-glutamyl transferase (gamma-GT), protein, glucose, specific gravity, bacteria, red blood cells and white blood cells. Serum samples were examined for urea, creatinine, inorganic phosphate and gamma-GT. Biochemical findings were compared with the degree of illness (clinical signs). Twenty one bitches had no signs of renal disease. Seventeen showed only glomerular damage indicated by proteinuria without signs of proximal tubular damage. Thirty seven bitches had increased urinary gamma-GT levels, indicating proximal tubular lesions, which were associated with proteinuria in 35 and renal failure in 16 of them, and worse clinical findings. In all bitches with pyometra serum levels of gamma-GT were comparable to values in control bitches. Glomerular dysfunction seemed to precede proximal tubular lesions, so that gamma-GT-uria in bitches with pyometra was not an early but rather a late indication of a more profound degree of renal dysfunction, that is, proximal tubular renal damage developed after glomerular dysfunction and preceding renal failure.