Probenecid and the rat kidney: investigations by renal enzyme excretion technique

Probenecid in doses of 640 mg/kg was administered to rats by the oral route, and the changes in five important enzymatic activities of urine were recorded thereafter for two days. The resluts exclude that probenecid impairs tubular reabsorption of low molecular weight protein, as urinary muramidase activity was not found increased. On the other hand, increased activities were encountered in those enzymatic activities in urine which derive from the renal tubular cells (ALD, G-6-PDH, LDH). These observations point towards a nephrotoxic effect of probenecid, which, however, is only of very low degree, as other "standard" enzymatic activities of urine, such as alkaline phosphatase, remained unchanged.