Effect of aminoglycosides on proximal tubular membranes of the human kidney.

The effect of the aminoglycosides amikacin, gentamicin, netilmicin sisomicin and tobramycin on the proximal tubule of the human kidney was investigated in 78 healthy subjects. Fifteen adults were each given gentamicin, sisomicin or tobramycin 3 mg/kg bodyweight, 10 subjects received netilmicin 3 mg/kg or amikacin 15 mg/kg additionally seven subjects amikacin 10 mg and six subjects netilmicin 6 mg on three consecutive days. The principal enzyme of the brush border membrane of the proximal tubule, alanine aminopeptidase (AAP), was determined enzymatically and immunologically in 24-hour urines. The effects of the various aminoglycosides on the membranes were different. Less of membrane AAP was greatest after amikacin and was least after tobramycin. There was no difference between gentamicin, netilmicin, and sisomicin, which had an effect intermediate between the other two compounds. The elimination of AAP occurred at intervals which might possibly have been caused by impairment of cell cycles.