Abstract

The effects of dehydroabietic acid (DHAA), a dominant resin acid in pulp and paper mill effluents, on membrane-connected events were studied in human erythrocytes. Fifty percent haemolysis was achieved by 252 microM DHAA after 1 h of incubation at +37 degrees C. At sublytic concentrations, DHAA protected erythrocytes against hypotonic haemolysis, with maximum protection occurring at 125 microM. In the lower range of sublytic concentrations, DHAA induced a slight echinocytosis; at higher sublytic concentrations erythrocytes were transformed to sphero-echinocytes and a release of acetylcholinesterase (exovesicles) occurred. Furthermore, at sublytic concentrations DHAA increased potassium efflux and passive potassium influx, while active potassium influx ((Na(+)-K+)-pump activity) and phosphate efflux were decreased. Our study indicates that DHAA acts on human erythrocytes in a way typical for amphiphilic compounds. It is proposed that DHAA by intercalating into the lipid bilayer of the membrane, affects the dynamics of the bilayer which in turn alters the permeability of the bilayer and the function of ion transporting membrane proteins.