Note on the Excretion of Phosphate during Water Diuresis

Abstract

The rate of phosphate excretion is independent of the water rate even when, owing to copious diuresis, the urinary phosphate is below the level of the plasma phosphate. This is inconsistent with the view that phosphate is a "no-threshold" substance as represented in Cushny''s theory of kidney secretion. The bearing of this result on other theories of kidney secretion is briefly discussed.