Persistence of the effects of ethanol in vitro on the lipid order and enzyme activities of chick-liver membranes.

Results demonstrate for the first time that ethanol exerts two different effects on the lipid order of chick-liver mitochondria and microsomes: a fluidizing effect both in the core and at the surface of the membrane, which depends on its physical presence, and a rigidization of the surface of these membranes which occurs after its removal. In addition, and directly related to the reduction in fluidity produced in the membrane surface after ethanol removal, we have detected a persistent alteration in different enzyme activities involved in the hepatic mitochondrial and microsomal electron-transport systems. The persistence of the alterations in the lipid order and enzyme activities may result from a structural rearrangement of the lipid and protein components produced in the lipid bilayer surface when ethanol is no longer present in the membrane.