The Water and Electrolyte Distribution Be- Tween Plasma and Red Blood Cells Fol- Lowing Intraperitoneal Injections of Isotonic Glucose*

In a previous paper (1) we have shown that the alterations in the cation concentrations of the plasma which result from adrenal insufficiency in the cat, are accompanied by similar changes in their concentrations in the red blood cells. These changes persist even after correction is made for the slight water shift to the cells, and we have concluded that a change in the plasma electrolyte pattern may so affect the red cell membrane as to make it somewhat permeable to cations. As has been pointed out in the previous paper, two serious objections may be raised to our interpretation of these results: (1) the altered permeability is not. due to the electrolyte change alone, but partly to a lack of cortical hormone which may play a part in the maintenance of normal permeability; (2) there has been no cation exchange at all, the cation differences which we have measured being due to the presence of new red cells of different cation contents which entered the circulation in the interim between the drawing of the two blood samples. These objections disappear if it can be shown that the cell cation concentrations still change when the plasma electrolytes are altered rapidly in otherwise normal animals. It is with the removal of these objections that the present paper is concerned. It has been shown by several authors (Gilman (2); Darrow and Yannet (3)) that large intraperitoneal injections of isotonic glucose solution will markedly alter the plasma electrolyte picture. Furthermore, the changes produced are very similar to those