Researches were executed on white rats with the body weight of 140–180 g. Unselected blockator NO-synthases Nw-NLA was introduced (1 mg/ 100 g of the body weight) 30 min before the functional kidney test. Renal activity was studied in conditions of salt loading by 3 % solution of sodium chloride in the volume of 5 % per the body weight. It was established that acute NO blockade was accompanied by decreasing of creatinine clearance and diuresis in conditions of salt loading by 3 % solution of sodium chloride. NO blockade results in decreasing of endogenous nitrates renal clearance and nitrites against a background of these substances concentration increasing in the blood plasma, as well as it was accompanied by changes of osmoregulating function of kidneys. It is shown in decreasing of renal clearance of osmotical active substances.
