Water and Sodium Excretion in Hormonally Hypertensive Rats

¹ From the Division of Research, The Cleveland Clinic Foundation and The Frank E. Bunts Educational Institute, Cleveland, Ohio

Osmotic diuresis with mannitol was used as a means of evaluating renal water and sodium reabsorption in uninephrectomized normotensive rats (I) and in rats made hypertensive by adrenal enucleation (II), and by injection of desoxycorticosterone acetate (III), cortisone (IV) or both hormones (V). All the hypertensive rats showed a diminished capacity for water reabsorption, tentatively attributed to potassium depletion. Sodium excretion patterns were not related to arterial pressure in any group, nor to glomerular filtration rate in groups I, III, IV and V. Rats with regenerating adrenals (II) showed some impairment of ability to retain Na during osmotic diuresis.