Abstract
The effects of oral administration of??-naphthylisothiocyanate (ANIT) on the microsomal membrane structure of rat liver were studied using the spin-labeling technique. Two different spin probes, 16-doxyl-stearic acid (16-DSA) and 5-doxyl-stearic acid (5-DSA), were used to assess the membrane fluidity. The rotational correlation time (τc) of 16-DSA decreased linearly, but temperature dependently, after ANIT administration; while it decreased sigmoidally in the control. Moreover, the levels of?Nc after ANIT administration were always shorter than those of the control between 22.5 and 37.5°C. On the other hand, the order parameter of 5-DSA incorporated in the ANiT-treated membrane did not differ distinctly from that of the control. These results suggest that ANIT or its metabolites injured the microstructure of the hydrophobic region rather than the surface region of the lipid bilayer in the membrane.
