EVIDENCE THAT PLASMA-MEMBRANE FLUIDITY OF ISOLATED HEPATOCYTES IS MODIFIED BY EXPOSURE TO MICROTUBULE-DEPOLYMERIZING DRUGS

The role of microtubules on membrane fluidity has been investigated on freshly isolated whole rat hepatocytes prepared by the perfusion method and exposed either to the microtubule-depolymerizing drugs colchicine and vincristine or to β-lumicolchicine, a colchicine analog deprived of biological activity. Exposure of hepatocytes to 6.3 μM colchicine or to 3.0 μM vincristine led to a significant decrease of membrane fluidity as measured by fluorescence polarization of trimethylammoniodiphenylhexatriene (TMA-DPH). No changes were observed in cells exposed to 10.0 μM β-lumicolchicine. These observations support the hypothesis that the microtubular system plays a role in the modulations of physico-chemical properties of the plasma membrane. © 1990.