Effects of Primaquine on the Red Blood Cell Membrane. Ii. K+ Permeability in Glucose-6-Phosphate Dehydrogenase Deficient Erythrocytes*

An unexplained anomaly of "primaquine-sensitive" erythrocytes is their ability to resist hemoly- sis in vitro, even when exposed to concentrations of primaquine that are greatly in excess of phar- macologic levels. Beutler, Dern and Alving They were unable to demonstrate any difference between normal and abnormal cells with respect to the drug concentration required to produce in vitro hemoly- sis. In vitro studies on normal cells, reported in an accompanying paper (2) generally demon- strated no hemolysis with concentrations of less than 5 x 10-3 M primaquine; these observations were made on whole defibrinated blood, and when compared with Beutler's studies of red cells sus- pended in buffered saline, it appears that serum proteins inhibited hemolysis of red cells exposed to concentrations of primaquine less than 5 x 10-3 M.