[Action of penicillin on the erythrocyte membrane].

The effect of the therapeutic concentrations of benzylpenicillin on potassium release and osmotic resistance of the red blood cells in healthy children was investigated potentiometrically with the use of a K+-selective electrode. In a concentration of 0.66 mM (370 units/ml) benzylpenicillin increased the total content of potassium in the cells and their resistance to osmotic lysis and lowered the rate of K+ release induced by valinomycin. The membrane stabilizing effect of benzylpenicillin observed in these studies could to some extent stipulate its nonspecific antiinflammatory effect. In a concentration of 1.32 mM (740 units/ml) it had no significant effect on the indices studied. Under the effect of the maximum concentrations of the antibiotic (3.3 mM) the signs of lowered stability of the red blood cell membranes were observed, i.e. an increased rate of the valinomycin induced release of K+ and a tendency for the decreasing of the osmotic resistance.