Effects of alcohol on membrane fluidity of human erythrocyte

Membrane fluidity in human erythrocytes was measured by a spin label method using an electron spin resonance spectrometer in healthy volunteers after ingestion of alcohol (1.5 ml of whisky/kg body weight). Fluidity in the lipid bilayer closer to the hydrophilic face decreased at 30 min and 90 min, and fluidity in the hydrophobic core decreased at 90 min after ingestion of alcohol. In the same experiment, the level of thiobarbituric acid reactive substances in the serum decreased 30 min after ingestion of alcohol, and the triglyceride level increased and free fatty acid level decreased, and serum superoxide dismutase activity increased 150 min after ingestion. Furthermore, membrane fluidity in human erythrocytes was examined in patients with alcohol dependence syndrome who had not any alcohol for about 26 months. Erythrocyte membrane fluidity of patients with alcohol dependence syndrome was not different from that of healthy controls. However, erythrocyte membrane fluidity of the lipid bilayer closer to the hydrophilic face increased in patients who had concomitant liver cirrhosis compared with those who did not. These results suggest that alcohol affects temporal change of membrane fluidity in human erythrocytes.