EFFECT OF EXPERIMENTAL DIABETES-MELLITUS ON GENTAMICIN-INDUCED ACUTE RENAL FUNCTIONAL-CHANGES IN THE ANESTHETIZED RAT

1. Rats with streptozotocin (STZ) diabetes are protected from gentamic in (GEN) nephrotoxicity, Because the chronic renal damage from GEN is preceded by acute renal functional changes (notably hypercalciuria), t he present study aims to determine whether diabetes may also protect a gainst the acute effects of the drug, If there is a link between the r apid physiological actions of GEN and its subsequent nephrotoxicity, t he former may also be affected by the diabetic condition, 2. Standard renal clearance techniques were performed on anaesthetized rats that h ad been injected with STZ or vehicle 2 weeks previously, All animals w ere infused with 0.9% NaCl for 5 h and then either GEN (0.28 mg/kg per min) or 0.9 % NaCl alone for 2 h, 3. Baseline fractional calcium excr etion (FECa) of diabetic rats was three-fold that of control animals ( 6.6+/-0.2 vs 2.2+-0.2%, respectively; P<0.01, MANOVA), Following GEN i nfusion, a comparable increase in FECa occurred in control and diabeti c rats (5.3+/-0.6 vs 5.3+/-0.8%, respectively; NS), 4. Streptozotocin diabetes, therefore, does not alter the acute hypercalciuric response to GEN, This may suggest that the acute effects of GEN on renal calciu m handling do not contribute to the subsequent nephrotoxicity. However , the higher baseline FECa seen in diabetic rats may afford protection against the renal injury caused by gentamicin.