Vanadyl ions increase the order parameter of plasma membranes without changing the rotational relaxation time

Differential polarized phase fluorometry of 1,6-diphenyl-1,3,5-hexatriene showed that vanadyl ions (VO2+) increased its limiting anisotropy (order parameter) in crude plasma membranes from brown adipose tissue of the golden hamster (Mesocricetus auratus). This was about 10(3) times larger than the effect of Ca2+ and was several times greater than the action of Co2+. Vanadate anions were without any effect. During the membrane treatment with VO2+, the rotational relaxational time of diphenylhexatriene did not change. This results suggest a possible positive influence of tetravalent vanadium on the stability of cell membranes.