OSMOTIC PROPERTIES OF THE ERYTHROCYTE

Abstract

The degree of hemolysis of ox erythrocytes produced by a given hypo-tonic NaCl soln. is not decreased by a previous exposure of from a few sec. to several hrs. to a similar but slightly less hypotonic non-hemolytic soln. Within this period the hemolysis method gives no evidence of any escape of osmotically active substances from the cells. After 3-4 hrs. in the case of ox erythrocytes, and from a few min. to an hr. in the case of those of the pig, cat, rabbit and man, there may be a gradual increase in osmotic resistance suggestive of a slow escape of salts. Solns. of sucrose, either hypotonic or isotonic, cause a striking increase in the osmotic resistance of erythrocytes; this occurs in 2 stages: a rapid one and a much slower one following the first after a considerable interval. While the slower change is probably associated with an escape of salts, the more rapid and more striking one, which is readily reversible, is interpreted as due to an exchange of anions from the cell for OH'' ions from the soln., the resulting increase in base bound by hemoglobin causing a decreased osmotic pressure within the cell. Calculations show that the expected osmotic effect of such an exchange is of the order of magnitude of that actually observed.