The effects of amphotericin B, an antifungal antibiotic, on erythrocyte volume and cation permeability were investigated by measuring the hematocrit, cell volume, cation content, fragility and osmotic behavior in rat erythrocytes, in vitro. 1. When erythrocytes were incubated in a Ringer solution containing amphotericin B (5-25 microgram/ml) the hematocrit and the cell volume increased, the effect being proportional to the concentration of the drug and the incubation time period. 2. Amphotericin B increased the Na content and decreased the K content of the erythrocyte. In normal Ringer solution (NaCl-Ringer)containing amphotericin B the magnitude of cellular Na gain was greater than that of K loss. Therefore, the total cellular cation content increased. On the other hand, when cells were incubated in the amphotericin B containing Ringer solution in which NaCl was replaced by Na2SO4 (Na2SO4-Ringer) the magnitude of cellular K loss exceeded that of cellular Na gain. Consequently, the total cellular cation content was reduced. 3. Amphotericin B increased cell volume (hematocrit) when erythrocytes were incubated in the Na2SO4-Ringer solution. 4. The fragility of erythrocytes increased when cells were preincubated in the amphotericin B containing normal Ringer solution, whereas it decreased in tile cells preincubated in the amphotericin B containing Na2SO4-Ringer solution. 5. The cell volume was linearly related to the reciprocal of medium osmolality(200 to 900 mOsm/kg H2O) in both NaCl-and Na2SO4-Ringer solutions, and the linearity was not altered by amphotericin B. The antibiotic did not change the slope of the correlation line (V vs. 1/OSM). It, however, increased the intercept of the line with the ordinate in normal Ringer solution and decreased that in the Na2SO4-Ringer solution. These results indicate that amphctericin B alters the cell volume by changing the permeability of Na and K across the membrane.
Amphotericin B/pharmacology* ; Animal ; Erythrocyte Volume/drug effects* ; Erythrocytes/analysis* ; In Vitro ; Osmotic Fragility/drug effects ; Potassium/blood* ; Rats ; Sodium/blood*