Changes in the water and sodium permeability of amphibian skin in the presence of the efferent plasma of "dehydrated dog kidney".

Two kidneys of the same dog were perfused separately with the same blood pool. After the control periods one of the kidneys was replaced by another one taken from a previously dehydrated dog. The presence of the "dehydrated kidney" resulted in a significant and almost immediate decrease in creatinin clearance of the contralateral perfused kidney. The Ccreat increased after the removal of the dehydrated kidney. Plasma samples were taken during the control, transplantation and recovery periods and their activity on the water permeability (osmotic water flow) and sodium transport was examined in amphibian skin. The presence of the plasma taken during the transplantation period resulted in a highly highly significant decrease in the osmotic water transport without any change in the sodium transport. This decrease was reversible, at least partly, after replacing the experimental plasma by a control one. These changes were not observed when a "desalted kidney" was used instead of the "dehydrated" one. These results suggest that in the status of dehydration the kidney releases some humoral factor or factors, which would induce a decrease in the measured GFR, possibly by a direct or indirect effect on membrane, probably glomerular membrane-permeability.