Gentamicin nephrotoxicity in young rabbits.

Gentamicin nephrotoxicity was investigated in 2 experimental models, Group I: young rabbits, age 10 to 12 d old (body weight 200 +/- 28 g) and Group II: growing rabbits, age 7 to 8 weeks old (body weight 1,470 +/- 116 g). Enzyme activity of Na-K-ATPase was measured in the inner cortex, the outer cortex and the medulla of the kidneys at 1, 1 1/2, 2 1/4, 3 and 4 h after a single injection of 150 mg per kg BW gentamicin and each result of group I was compared to that of group II. In group II animals, increase of this enzyme occurred in both the inner cortex and the outer cortex but not in the medulla, and changes occurred earlier in the outer cortex than in the inner cortex. In group I, the change of this enzyme activity was seen in the inner cortex only and occurred much later than in group II. These results indicate that gentamicin nephrotoxicity occurs earlier in adult rabbits than in young rabbits and also the change in enzyme activity was seen only in the inner cortex in the young rabbit kidney.