Vitamin E deficiency has different effects on brain and liver phospholipid hydroperoxide glutathione peroxidase activities in the rat.

The effect of vitamin E deficiency on glutathione peroxidase activity (GPX) and on the activity of a selenoenzyme (phospholipid hydroperoxide glutathione peroxidase (PHGPX) was measured in rat brain and liver. In brain, the activity of both enzymes was in the same range in homogenate and in microsomes. In contrast, in liver homogenate, PHGPX activity was approximately 20 times lower than that of GPX. Very interestingly, PHGPX activity was significantly decreased in brain microsomes by vitamin E deficiency, but slightly significantly increased in liver microsomes. In contrast, GPX activity was not affected in brain by vitamin E deficiency, but was significantly lower in liver homogenate and microsomes. Thus, PHGPX activity is partially controlled by vitamin E in membranes, and PHGPX is probably an enzyme different from GPX.