Increased sodium reabsorption postuninephrectomy: evidence for a humoral factor.

Natriuresis occurs in the immediate postnephrectomy period. Yet in the days and weeks that follow, increased Na-K-ATPase (sodium-potassium activated adenosine triphosphate) activity, oxygen consumption and sodium reabsorption occur. Increased sodium reabsorption probably occurs early postuninephrectomy but is obscured by passive hemodynamic and physical-chemical factors that induce natriuresis. These factors were controlled in isolated canine kidneys perfused with normal and twenty-four-hour postuninephrectomized blood. A substance that increases sodium reabsorption and glomerular filtration rate in the kidneys perfused with uninephrectomized blood was demonstrated. The relationship between this and a hormonal substance that induces compensatory renal hypertrophy is unknown. The use of this hormone for treatment of renal failure is discussed.