TRANSFORMATION AND RESTORATION OF BICONCAVE SHAPE OF HUMAN ERYTHROCYTES INDUCED BY AMPHIPHILIC AGENTS AND CHANGES OF IONIC ENVIRONMENT

1. 1. The biconcave discoid shape of normal human erythrocytes can be altered reversibly by a great number of amphiphilic agents. Crenated cells are induced, as a rule, by anionic or non-ionized compounds; cup-like cells by cationic substances. Formation of crenated and cup cells probably is induced by interaction of the transforming agents with sites charged oppositely within the membrane. 2. 2. Compounds inducing crenation or cup formation can be regarded as true antagonists, since either group of compounds regularily brings about complete reversal of shape transformatins induced by the other one. 3. 3. Suspending erythrocytes in isotonic solutions of non-penetrating anions leads to the occurrence of cup cells, the extent of transformation becoming more pronounced with lowering of extracellular pH. Restoration of normal shape under these conditions is accomplished by addition of penetrating anions. The concentrations of these anions necessary to produce 90% normalisation increase with fall of pH. This type of cup formation supposedly is induced by the increase above a critical value of the pH difference between erythrocyte membrane and adjacent media. 4. 4. The results point to a great lability of the interactions of structural elements of the erythrocyte membrane responsible for the maintenance of biconcave shape. They suggest this shape to result from an equilibrium between opposite forces directed towards formation of crenated or cup cells, respectively. © 1968.