Influence of enalaprilat, angiotensin converting enzyme inhibitor, on a functional proteinuria associated with increase in diuresis unduced by furosemide, 1-deamino-arginine vasotocin (1d-AVT) injection or water loading was investigated in experiments with Wistar rats. Intraperitoneal injection of 0.1 mg/100 g b.w. of enalaprilat resulted in reduction of glomerular filtration rate, solute-free water reabsorption and solutes excretion, particularly potassium excretion, after 1d-AVT administration and decrease in diuresis and solute-free water excretion after oral water loading. Enalaprilat injection did not influence on the level of proteinuria induced by the various types ofdiuresis and albuminuria during water diuresis and 1d-AVT-dependent saluresis. The data obtained have shown that decrease in angiotensin II production in the renal structures does not affect protein excretion rate during examined forms of proteinuria and suggest existence of a multicomponent system of the pressure stabilization in the glomerular apparatus.