The renal and electrolyte response to respiratory acidosis in the adrenalectomized rat.

The renal response to respiratory acidosis is characterized in the rat"2 and in the dog' by chloruresis, a negative chloride balance, an elevated tubular reabsorption of bicarbonate with renal conservation of bicarbonate, and increased urinary excretion of acid. The depression of chloride and elevation of bicarbonate in the serum at equilibrium during sustained exposure to carbon dioxide depend on these changes in renal tubular function. It has been shown that exposure to carbon dioxide stimulates adrenocortical activity in the dog,' and in the rat.`' Both aldosterone and hydrocortisone accelerate renal tubular sodium-hydrogen and sodium-potassium exchange;8 the former reaction is important for tubular reabsorption of bicarbonate. In adrenal insufficiency there is impaired renal excretion of acid in response to metabolic acidosis.'° These relationships motivated the present study of the renal response to respiratory acidosis in adrenalectomized rats. It is tconcluded that the chloruresis and increased tubular reabsorption of HCO3 produced by respiratory acidosis are not dependent on adrenal cortical hormones.