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

The alterations of the passive electrical parameters (the permittivity ε and the electrical conductivity σ) 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 εs and the permittivity εp and electrical conductivity σp 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 α-dispersion and the high-frequency β-dispersion. Our results show a marked increase of the membrane permittivity εs close to a glucose concentration of 20 mM. 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.