ALTERATIONS IN BRAIN LIPID-COMPOSITION CAUSED BY VANATE

In an attempt to investigate the effect of sodium metavanadate on membrane lipids in rat brain, in vivo and in vitro experiments were carried out. Intraperitoneal administration of vanadate (10 and 16 .mu.mole/100 g) caused increase in cholesterol levels, whereas phospholipid levels were much less modified. These alterations brought about a significant increase in the ratio cholesterol/phospholipid. Concomitantly, an increase of both linoleic and docosahexanoic acids was observed, whereas arachidonic acid level was diminished. In all in vivo experiments the most effective dose on the parameters studied was 16 .mu.mole/100 g. On the other hand, when vanadate (10-3-10-5 M) was added in in vitro experiments a similar pattern of variation was obtained in cholesterol and phospholipid levels; however the variations were much less evident, 10-3 M being the most effective dose. Likewise in the in vivo experiments, vanadate seems to act by increasing the levels of linoleic and docosahexanoic acids and by decreasing the arachidonic acid level. In contrast, the docosahexanoic acid level remained unchanged in in vitro experiments. These results suggest that both the brain .DELTA.6 desaturase and extracerebral docosahexanoic acid synthesis are modified by vanadate. In conclusion, the present study indicates that vanadate is able to modify the cerebral lipid metabolism by altering the ratio cholesterol/phospholipid which in turn could lead to alterations in the membrane fluidity.