1. Eight rats developed detectable glutathione-S-transferase activity in their urine after three daily injections of toxic doses of gentamicin.
2. Seven of the eight rats had immunodetectable ligandin in their urine at this time.
3. The level of enzyme activity correlated well with the degree of elevation of serum creatinine.
4. This confirms ligandinuria and urinary glutathione-S-transferase as markers of acute renal proximal tubular injury.