Abstract
To elucidate the mechanism(s) of the relieving effect of saline on cephaloridine (CER) nephrotoxicity, rats were given CER in equal quantity (1g/kg body weight; i.v.), but at two different concentrations (4 and 25%) in saline. Urinary excretion of glucose, which was investingated as an index for renal proximal tubular injury, revealed that the renal damage was less in the 4% CER 25ml/kg group than in the 25% CER 4ml/kg group. As to urinary excretions of CER, sodium, potassium and water, no significant differences were observed between the two groups in the first 2 h, but chloride in the 4% CER 25ml/kg group showed higher values than in the 25% CER 4ml/kg group. Plasma concentrations of sodium, potassium, chloride and CER, did not show any definite distinctions between the two groups. At the time-point of 20min after the CER administration, renal CER content was significantly lower in the 4% CER 25ml/kg group than in the 25% CER 4ml/kg group. These results suggest that the sodium ion which is needed for cellular trapping of CER is competitively expended for cellular entry of the chloride ion in the kidney, and that the relieving effect of the saline on CER nephrotoxicity is ascribable to the loaded quantity of chloride ion.
