REACTIONS OF WHITE RATS’ KIDNEYS TO SMALL DOSES OF SODIUM NITRATE

Abstract

THE AIМ of the investigation was to study activity of rats’ kidneys under conditions of a single and chronic administration of small doses of nitrites. MATERIALS AND METHODS. The work was performed in white male rats. Effects of a single dose of sodium nitrite (0.2 mg/100g of body mass) against the background of 5% water load were studied in mature rats with body mass 95110 g (n=20). Chronic administration of sodium nitrite was fulfilled by watering the animals (body mass 190260 g) with water solution of sodium nitrite (50 mg/l) during 7 days (n=10). In addition, a series of experiments were carried on with a simultaneous watering with water solution of sodium nitrite (50 mg/l) and capropril (10 mg/l) during 7 days (n=20). The results obtained were compared with the controls of the same age 15 rats in each group. The function of kidneys was investigated under conditions of 5% water load. RESULTS. It was found that small doses of sodium nitrite when given once or chronically caused reliably decreased creatinine clearance and elevation of renal excretion of protein. It was also shown that captopril at chronic administration of nitrites failed to abolish the decrease of creatinine clearance and the increase of proteinuria. CONCLUSION. 1. A single or chronic administration of small doses of sodium nitrite to white rats results in decreased creatinine clearance and elevated excretion of protein. 2. Chronic administration of small doses of sodium nitrite is followed by accumulation of nitrites in the extracellular fluid. 3. The simultaneous chronic administration of ACEinhibitor and small doses of sodium nitrite facilitates further increase of protein excretion by the kidneys against the background of lower value of creatinine clearance. 4. Blockade of ACE with captopril influences the renal transport of exogenous nitrites and nitrates and the state of the nitrogen oxide cycle.