Enhanced urinary trypsin inhibitory activity in gentamicin-induced nephrotoxicity in rats.

Abstract We delineated in rats, the relationship between trypsin inhibitory activity in the urine and the nephrotoxic effects of gentamicin, eg, proteinuria and deterioration of glomerular filtration rate (GFR), measured by creatinine clearance. Gentamicin, 70 mg/kg per day, was injected intraperitoneally for 6–10 successive days. Serum and urine gentamicin levels were determined by a microbiological test. Trypsin inhibitory activity was assayed by the casein digestion method. The results showed a steady increase in urinary trypsin inhibitory activity starting from the fourth injection day. The increased levels of urinary trypsin inhibitory activity were associated with increased levels of urinary gentamicin excretion ( r = 0.36, p n = 50 after the fourth injection day), and were significantly higher than in control groups ( p r = −0.45, p