Effect of furosemide upon extracellular fluid volume depletion and kidney denervation in rats

The effect of the diuretic Furosemide (4 mg/kg) is tested on rats housed in metabolic, cages. The excretory function of the kidneys is studied over a 2-hour period after Furosemide administration, according to the following parameters: diuresis, glomerular filtration, excretion and excretory functions of sodium, potassium, chlorine and total osmotically active substances. Reduction of the volume of the extracellular fluid (ECF) is induced by intraperitoneal administration of 0.3 M glucose solution in amount equal to 10 per cent of the body mass. Comparative studies are carried out in animals with intact kidneys (IK) and with bilaterally denervated kidneys (DK). The decreased ECF volume is found to limit strongly the diuretic and saliuretic effect of Furosemide. In the experimental animals with DK, the reduced ECF volume reduced the diuretic and saliuretic effect of Furosemide to a considerably lesser extent. In euvolemic animals Furosemide has potentiated effect in the case of DK. The conclusion reached is that intact kidney innervation is necessary for the Na-retaining function of the kidneys in the case of depleted ECF volume.