Alterations of Protein Distribution Between Corpuscles and Plasma by Isotonic and Hypertonic Solutions

Abstract

One of us (Scott 1 ) observed that upon the addition of isotonic saline to whole blood in vitro, the total protein of the plasma was greater than in the original plasma; in other words, some protein had entered the plasma from the corpuscles. We have repeated these experiments and confirmed the observations as regards isotonic solutions, but when hypertonic solutions are used, the reverse occurs; there is a decrease in the total plasma protein, indicating that some protein had entered the corpuscles from the plasma. When hypertonic solutions were added to plasma alone, a decrease of protein did not occur, the total protein in the diluted specimen corresponding to the total in the control. Whether isotonic or hypertonic solutions were added to blood, the non-protein nitrogen of the plasma invariably increased.

The principle used was that employed by Scott. The corpuscle and plasma percentages were determined in duplicate by the hematocrit. The nitrogen determinations were made in duplicate by the modified micro-Kjeldahl method of Cavett, 2 including the use of H₂O₂ 3 to complete the oxidation. 0.8 cc. of plasma was used for the total nitrogen determination and what would be equivalent to 2.5 cc. of plasma for the non-protein nitrogen, the protein-free filtrate being prepared according to the tungstic acid precipitation of Folin and Wu. 4 Duplicate blanks were run in all the determinations. Oxalated blood was used in all experiments except where the procedure involved the use of CaCl₂ as a diluent, in which case defibrinated blood was used. Similar results were obtained with either type of blood.

A typical experiment is outlined below:

To make the results comparable, we have expressed them as if in each experiment we started with enough blood to have 100 cc.