Effect of insulin on lipid bilayer viscoelasticity.
Changes in the Young elasticity modulus in perpendicular direction to the membrane surface E perpendicular, in the coefficient of dynamic viscosity eta, in the electric capacitance C, in the surface charge U1, in the conductivity g and in the coefficient of non-linearity beta of current-voltage characteristic caused by insulin were studied in bilayer lipid membranes (BLM) prepared from a mixture of egg lecithin and cholesterol (4:1, w/w) in n-heptane. Even relatively small concentrations of insulin in electrolyte (ci approximately 4.8 x 10(-11) mol/l) caused a diminution in parameters E perpendicular and eta. Negative surface charge emerged on the membrane due to the insulin absorption, and U1 gradually increased depending on the concentration of the hormone in the electrolyte. Addition of insulin was also followed by an increase in membrane conductivity and affected the value of the coefficient of non-linearity beta of current-voltage characteristic. The effect of insulin on the BLM structure was discussed on the basis of the results obtained.
Hianik
T
T
Department of Biophysics, Faculty of Mathematics and Physics, Comenius University, Bratislava, Czechoslovakia.
Zórad
S
S
Kavecanský
J
J
Macho
L
L
D004548:Elasticity; D004553:Electric Conductivity; D007328:Insulin / Q000494:pharmacology*; D008051:Lipid Bilayers; D008564:Membrane Potentials; D013499:Surface Properties; D014783:Viscosity
D007328:Insulin; D008051:Lipid Bilayers