Sodium, potassium and osmolality of human and canine erythrocytes— Interest of trapped plasma and water content for their full significance

Abstract

1. 1. Sodium, potassium, osmolality were measured on dog ( Canis familiaris) and human erythrocytes. 2. 2. High-speed centrifugation (15,000 g) had no deleterious effect on electrolyte content; P O 2 and P CO 2 did not induce variations. 3. 3. Sucrose 14C gave a reliable value for trapped plasma. Water content was necessary to compare erythrocytic and plasma concentrations. 4. 4. Bound water is useful because only solute water should be used in calculations. Bound water was estimated by comparison of plasma and RBC osmolalities and represented about 6 per cent of total water. 5. 5. Canine erythrocytic and plasmatic fluids are more concentrated than human ones.