Insulin-induced changes in mechanical characteristics of lipid bilayers modified by liver plasma membrane fragments

Insulin interaction with BLM with incorporated fragments of rat liver plasma membranes, containing hormone receptors, was studied by determining Young modulus of elasticity of bilayer lipid membranes in direction perpendicular to the surface, E. The presence of membrane proteins in a concentration of 60 micrograms.ml-1 induced a significant decrease in parameter E (to approx. 50%) as compared with values obtained in non-modified membranes during insulin action (concentration interval 10(-11)-10(-9) mol.l-1). The extent of the effect was dependent on the initial phase state of the membrane, on cholesterol content in BLM as well as on membrane proteins concentration in lipid bilayer.