SODIUM DEPLETION AND RENAL CONSERVATION OF WATER*

Abstract

Rats depleted of Na and rendered hyponatremic by peritoneal dialysis develop severe, reversible impairment of renal concentrating ability, resulting in increased urinary losses of water, rapid weight loss and eventual restoration of serum Na to the normal range. The contri-bution of bone Na to replacement of Na deficits under these circumstances is negligible. Removal of Na from the diet does not change maximal urinary concentration in the rat if serum Na is unaltered and protein in-take is kept constant.