Alteration of Erythrocyte Membrane Fluidity by Heavy Metal Cations

Abstract

Fluorescence polarization measurements were carried out on ery throcyte ghosts treated with heavy metal cations. Membranes labelled with the fluorescent lipid probe all-trans 1,6-diphenyl-1,3,5- hexatriene (DPH) had increased DPH polarization (P) values, con sistent with increased membrane lipid viscosity, when treated with 10^-3 -10^-2 M of the chloride salts of cadmium, zinc or lead for 1 hour at 37° C, but not with calcium. Using cadmium as a prototype heavy metal, additional studies showed that exposure of ghosts to cadmium also increased the native protein fluorescence polariza tion. These increases in P values were observed at temperatures ranging from 15-40° C. These data suggest that interaction of cad mium and other heavy metals with cellular membranes may alter membrane lipid and possibly membrane protein fluidity, which may contribute to abnormal cellular function.