[Osmotherapy of acute kidney failure with special reference to plasma renin activity and mineral balance]

13 dogs were used to generate an acute toxic renal failure by sublimate. The alterations both of plasma renin activity (PRA) and of the acid-base and mineral balance were observed in uremia and after "osmotherapy" with mannitol (13 dogs). In the course of toxic renal failure the PRA increases on the average. A decompensated metabolic acidosis with general transmineralization is observed. Since in the stage of anuria the Na+ in urine fails to reach the macula densa cell canicularly, the theory is advanced that only the intracellular sodium in the macula densa cell is responsible for the regulation of the position of the vas deferens. Following "osmotherapy" the PRA is significantly lowered. The acidosis is still worsened under conditions of anuria. For the regulation of renin it has to be assumed that the enzyme in acute anuria after osmotherapy is being altered especially by volume receptors. Thus, osmotic therapy seems to be reasonable only with existing residual diuresis. This is valid especially for the administration of mannitol, because this substance remains strictly outside the cell.