[Studies on the nephrotoxicity of aminoglycoside antibiotics and protection from these effects. (1). Nephrotoxicity of gentamicin and mercuric chloride].

The present study was designed to find useful markers for detection of renal damage due to gentamicin (GM). Following the administration of 80 mg/kg GM, there were significant increases in urinary protein contents and alkaline phosphatase, N-acetyl-beta-glucosaminidase, lactate dehydrogenase, gamma-glutamyl transpeptidase and lysozyme activities. Alterations of these parameters had a peak at the 7th or 10th day and values restored to near normal levels by the 15th day. Light microscopic observations of the kidney on the 10th day showed mainly the necrosis of proximal tubular epithelial cells in the renal outer cortex, and there was regeneration of epithelial cells on the 15th day. In addition, when 1 mg/kg HgCl2 was given to rats, there were increases in urinary enzyme activities and protein contents, and BUN. The kidney of rats that received HgCl2 showed the necrosis of tubular epithelial cells in the renal inner cortex. It is considered from these results that determination of the activities of various urinary enzymes may be useful markers to detect tubular damage induced by GM.