D-glucose-induced alterations in the electrical parameters of human erythrocyte cell membrane

The alterations of the passive electrical parameters (the permittivity epsilon and the electrical conductivity sigma) of human erythrocyte cell membrane induced by the presence of glucose in the extracellular medium have been investigated by means of dielectric spectroscopy measurements. The membrane permittivity epsilon(s) and the permittivity epsilon(p) and electrical conductivity sigma(p) of the cytosol have been evaluated on the basis of a recent analytical model proposed by Prodan et al., 1983 [16], that takes into account the whole dielectric spectrum of a cell suspension, consisting of both the low-frequency alpha-dispersion and the high-frequency beta-dispersion. Our results show a marked increase of the membrane permittivity epsilon(s) close to a glucose concentration of 20mM. On the contrary, the electrical properties of the cytosol do not change appreciably. This finding strengthens the hypothesis that glucose interactions involve primarily the cell membrane and the mechanism of the transport is briefly discussed.