Specificity of acute effects of Cd on renal function

Renal reabsorption of a typical low-molecular weight protein (cytochrome c) by rats was compared in controls and in rats acutely poisoned with CdCl2 (20 mumol/kg i.p., together with 300 mumol mercaptoethanol), HgCl2 (3 mg/kg i.m.), or NiCl2 (10 mg/kg i.p.). The effects of these metals on reabsorption of filtered cytochrome c were expressed in terms of changes induced in total protein excretion and in urinary concentrating ability. On this basis, only Cd exerted an acute specific effect on transport of cytochrome c, similar to its production of low molecular weight proteinuria following chronic exposure. At the time of the experiments the animals contained only low Cd levels in the renal cortex (7 micrograms/g). We conclude that the acutely injected rat can serve at least to some extent as a valid model for the study of Cd nephrotoxicity and that cytochrome c is a useful probe for the study of Cd-induced low molecular weight proteinuria.