In vitro effects of thyroliberin on structural state of plasma membranes in mouse brain and liver.

The spin probe method was employed to study in vitro the effect of regulatory peptide thyroliberin on structural state of surface (0.8 nm) and deep (2 nm) lipid layers of the plasma membranes in mouse liver and brain. Thyroliberin in a concentration range of 10(-3)-10(-18) M enhanced structural order of surface lipids, the maximum effect was observed at 10(-9)-10(-10) M. The dose-effect dependencies for microviscosity of deep lipids were nonlinear and had 3 extrema at 10(-4)-10(-7) M, 10(-9) M, and 10(-14)-10(-16) M. The greatest changes in lipid microviscosity produced by 10(-9) M thyroliberin are explained by lipid-receptor interaction.