[The protective effects of metallothionein on membrane proteins against endothelin--electron paramagnetic resonance...

Using EPR spin labelling 5 NS, 16 NS (for fatty acids) and MSL (for proteins), the changes in lipid fluidity and protein conformation in the ghost erythrocyte membrane of rat treated by endothelin have been studied. The results showed that the lipid fluidity in both of the polar region and the hydrophobic core in the membranes was not altered by endothelin at the concentration of 1 x 10(-9), 1 x 10(-8) and 1 x 10(-7) mol/L, but the ratio of S/W of membrane proteins was significantly changed by endothelin at 5 x 10(-9) and 1 x 10(-7) mol/L. This means that endothelin at the dosages used did not affect the membrane lipids but did alter protein conformation. Metallothionein (1 x 10(-5) mol/L) could attenuate this change and protect membrane proteins from endothelin. However, there is no effect of metallothionein on membrane proteins.