The Effect of Some Neutral Macromolecules on the Pattern of Hypotonic Hemolysis

Three neutral polymers, ficoll, dextran and polyethyleneglycol, all inhibit hemoglobin liberation in hypotonic electrolyte solutions. If red cells are suspended in a hypotonic solution which, in the absence of a polymer, would hemolyse all the cells, only a part of the hemoglobin is liberated. The polymer does not alter the fragility but only the amount of hemoglobin liberated from the individual cells. The inhibitory effect is proportional to the weight concentration of the polymer and independent of the mol. wt. within wide limits. The inhibitor molecules must presumably have a critical minimal size since the trisaccharide raffinose did not inhibit hemoglobin liberation under similar conditions. From the data on the lowest molecular weight dextran fraction it was concluded that the lower limit for dextran was below a molecular weight of about 1700. Complete inhibition of hemoglobin liberation was never obtained and from the evidence available it is suggested that the first 20 per cent, at least, of the hemoglobin may escape with a bulk outflow. The colloid osmotic relationships of the cell during and after hemolysis are discussed and it is concluded that cannot be decided whether the polymer effect is colloid osmotic in nature.