Cortisone-induced polyuria following hypophysectomy

Abstract 1. 1. A study has been made of the nature of the polyuria induced by cortisone occurring in two patients who had undergone hypophysectomy. 2. 2. In these two patients the polyuria has been shown not to be due to an increase in the load of urinary solute nor to deterioration in those renal functions concerned with water conservation. 3. 3. The view that the phenomenon is due to primary polydipsia seems inescapable. A review of the literature suggests that this mechanism is probably responsible for the syndrome in similar patients described by other workers, with the exception of the patient reported by Leaf et al. [2] in whom alteration in solute load determined the increase in urinary volume. In these circumstances it is inappropriate to refer to the syndrome as diabetes insipidus. 4. 4. In our patients the administration of cortisone has been shown to improve the renal capacity to absorb solute-free water during osmotic diuresis under conditions of hydropenia. 5. 5. This effect is discussed in the light of the Wirz countercurrent hypothesis and in relation to the view that the action of ADH is one of increasing the permeability of the renal tubules to the movement of water along osmotic gradients. The increase in solute-free water reabsorption brought about by cortisone might then be explained by the effect of the steroid in augmenting reabsorption of sodium.