EFFECT OF HYPERTONIC SOLUTIONS ON METABOLISM AND EXCRETION OF ELECTROLYTES

Abstract

Hypertonic solns. of glucose, mannitol, and urea were injd. into normal human subjects. Glucose and mannitol were apparently confined largely to the extracellular fluid; by elevating the effective osmotic pressure of the serum, they depressed the concn. of serum Na and withdrew water from the cells. Both substances sharply augmented the Na excretion, whereas urea, injected in comparable amts., produced only minor changes. From this and other evidence the state of hydration of body cells is assumed to be a factor regulating the excretion of Na. Injns. of hypertonic solns. produce a slight increase in K excretion during dehydration and a slight decrease during water ingestion. Cellular transfers of K tend to prevent changes in the concn. of serum K which might otherwise follow changes in extracellular volume. The excretion of P is depressed by mannitol and accelerated by glucose. Urea requires less water for its excretion than does glucose or mannitol. The effects of hypertonic solns. on the metabolism and excretion of water and electrolytes are apparently not detd. by the osmotic pressure of the tubular urine, but depend instead upon the metabolic and osmotic properties of the admd. solute, the character and distr. of the electrolyte, and the previous state of the organism.