RENAL MECHANISMS OF REGULATION OF THE NITROGEN OXIDE CYCLE IN WHITE RATS LOADED WITH SODIUM NITRITE

THE AIM of the investigation was to study the renal transport of nitrates and nitrites in the intact kidney. MATERIALS AND METHODS. The selected for the experiments male rats with body mass 100200 g were randomly divided into 4 groups. The rats of the third and fourth groups were given sodium nitrite (0.2 mg/100g of body mass). The kidney function was studied under conditions of induced diuresis. Water and 3% solution of chemically pure sodium chloride (osmolality of the solution was 3 and 1050 mOsm/kg H2O) was used as a load which was administered by an intragastric probe at 5% of body mass. Water or aqueous solution of sodium nitrite was administered to rats of the 1st and 3rd (n=12) groups respectively. Saline solution was administered to rats of the 2nd group (n=13), the saline solution with sodium nitrite was administered to rats of the 4th (n=12) group. Nitrites, nitrates, creatinine and urine protein were determined in samples of urine and blood plasma. RESULTS. It has been found that a single administration of sodium nitrite, independent of the kind of load, is followed by a decrease of creatinine clearance, elevation of protein eliminated by the kidneys and does not result in higher concentration of nitriteions in blood plasma. At the same time the concentration of nitrites in blood plasma and their excretion by the kidneys increased. CONCLUSION. 1. Administration of sodium nitrite (0.2 mg/100g of body mass) results in the increased concentration of nitrates rather than nitrites in blood plasma and is followed by a moderate change of the functional state of the kidneys: lower creatinine clearance and higher excretion of protein. 2. The investigations performed suggest that detoxication of organism after administration of exogenous nitrites is realized at the expense of their accelerated oxidation into nitrates followed by higher rate of excretion of nitrateanion by the kidneys. 3. The kidneys play an important role in regulation of the nitrogen oxide cycle in organism after administration of exogenous sodium nitrite.

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