Abstract
Some effects of the clinically important fungicidal antibiotic amphotericin B on the transport of phosphate, sulphate and potassium ions across the membrane of the human erythrocyte were investigated. In general, amphotericin B inhibited the transport of the anions to about the same degree and stimulated the transport of the cation. At low concentrations, the inhibition of both phosphate and sulphate ion transport was concentration-dependent. A plateau was reached at 47 and 52% transport for phosphate and sulphate, respectively, beyond which no further inhibition was obtained. In contrast, the initial rate of potassium ion release from erythrocytes was stimulated. This effect was also concentration-dependent. The observed stimulatory effect on cation efflux was attributed to penetration of the antibiotic into the membrane of the erythrocyte, leading to the formation of specific channels. The inhibition of transport of anions, however, was attributed to alteration in the fluidity of the lipid bilayer consequent to channel formation.