EFFECT OF MERCURIC IONS ON HUMAN ERYTHROCYTES .1. RATE OF HEMOLYSIS INDUCED BY OSMOTIC SHOCK AS A FUNCTION OF INCUBATION-TIME

Incubation of human erythrocytes with mercuric ions for 5 min causes a transient increase in mechanical resistance as measured by osmotic sh ock. After a longer incubation time (necessary for the metal to cross the cell membrane), cells recover their normal fragility; however, aft er 10-20 min of exposure to mercuric ions haemolysis occurs in the inc ubation vessel. In contrast, p-chloromercuribenzenesulfonate (a compou nd known to bind mainly to band 3 of the cell membrane without passing into the cell) increases the osmotic resistance of erythrocytes, as o bserved transiently for mercuric ions, but does not induce haemolysis even at incubation times of 20-30 min. Therefore it seems that the int eraction per se of mercuric ions with the membrane does not represent the main damaging event and therefore the toxicological effect of merc uric ions must be mostly related to subsequent processes, such as the interaction of the metal with intracytoplasmic components and/or disru ption of the cytoskeleton.