Micropuncture study of the effect of various diuretics on sodium reabsorption by the proximal tubules of the dog.

Open Access
Publisher Website
Google Scholar
Abstract
The effect of various diuretics on fluid reabsorption in the proximal tubule of the dog was investigated by micropuncture technique using repeated collections from identical tubule segments during control and experimental phases. After the administration to hydropenic dogs of ethacrynic acid or chlormerodrin there was a significant increase in the fraction of the glomerular filtrate reabsorbed in the proximal tubules. This increase in reabsorption was markedly reduced or abolished when the fluid lost as a result of the diuresis was replaced with isotonic saline solution. Furosemide and hydrochlorothiazide in hydropenic animals also produced significant increases in proximal reabsorption does not contribute significantly to the diuresis produced in dogs by ethacrynic acid, chlormerodrin, furosemide, and hydrochlorothiazide. The increased reabsorption observed appears to be a consequence of acute depletion of extracellular volume, a response opposite to that produced by infusion of saline.