Effects of Gentamicin on Glomerular Renin Release

Gentamicin nephrotoxicity is associated with impaired glomerular function. To examine whether the effects of gentamicin on glomerular function are mediated through alterations in the renal-angiotensin system, basal and stimulated glomerular renin release was assessed in isolated glomeruli from control and gentamicin-treated rats. Male Sprague-Dawley rats (220 ± 20 g) were studied immediately after treatment with gentamicin sulfate (4 mg/kg BW/day, n = 6) for 1 or 2 consecutive weeks and after 1 week of recovery from 2 weeks of treatment. Control rats received an equivalent volume of saline (n = 9). After the respective treatment, renal renin content was measured. In addition, glomeruli from control and gentamicin-treated rats were isolated and glomerular renin release was measured under basal conditions and after stimulation with the calmodulin inhibitor trifluoperazine (1 × 10−4 M). Renin concentration was determined in aliquots of the supernatant by measuring the generation of angiotensin I using radioi...