After a combined 14 days introduction of cadmium chloride (0,1 mg/kg intraperitoneally) and sodium nitrate (500 mg/kg intragastrically) to mature nonlinear albino rats with “slow” type of acetylation changes of water-electrolytic metabolism were manifested by 6,3 % increased concentration of sodium ions in the blood plasma. Hypernatremia resulted from the disorders of water, ion, and osmoregulatory renal functions induced by both nephrotoxic substances. Stability of potassium metabolism indices was indicative of the retention of a functional state in the distal portion of the nephron. The combination with sodium nitrate restrained a harmful effect of cadmium chloride on the glomerular sector of a nephron and glomerular filtration rate (GFR) did not change. Taking into account the lack of activation of glomerular processes in response to penetration of exotoxins into the body GFR can be considered as a predictor of nephropathy progression in rats with “slow” type of acetylation. 6,9% increase of proximal reabsorption of sodium ions under conditions of stable GFR was indicative of disorders of the glomerular-tubular balance due to dysfunction of the nephron proximal portion. At the same time, it is reasonable to present the evidence of our opinion by the analysis of interrelations between the indices of functional-biochemical kidney conditions considering biochemical criteria of acetylation type in mature rats with “slow” acetylation type under conditions of a combined effect of cadmium chloride and sodium nitrate, which are the prospects of further investigations.