THE EFFECT OF DAMAGE TO VARIOUS PARTS OF THE RENAL TUBULE ON THE EXCRETION OF PHOSPHATE BY THE DOG'S KIDNEY

Abstract

The first third of the proximal tubules of the left kidney in dogs was damaged by the injection of 2.5 mg% potassium dichromate, the last two thirds by the injection of 0.5% sodium tartrate, and the distal tubules by the retrograde injection up the ureter of 0.05% mercuric chloride. Damage to the first third of the proximal tubule resulted in marked increase in phosphate excretion. Damage to the last two thirds of the proximal tubule had no significant effect on the output of phosphate. When the distal tubule was damaged the excretion of phosphate was greatly reduced. The results indicate that phosphate is reabsorbed in the first third of the proximal tubule and actively excreted by the distal tubule.