Fluidity changes in rat liver plasma membranes during regeneration

The fluidity of the liver plasma membrane during the first cell cycle of hepatectomized rats has been investigated by means of stearic acid spin labels and of the fluorescence polarization of perylene. The order parameters of 5-doxylstearate, that probes the membrane surface, have been found lowered in the hepatectomized rats after 15 hours from operation, in comparison with anesthetised and sham-operated controls at the same time; on the contrary, the fluidity in the membrane core, as probed by 16-doxylstearate, is increased in all groups. The fluorescence polarization of perylene is also lower in the hepatectomized rats. The results suggest that liver regeneration is accompanied by a fluidity increase of the plasma membrane.