Localization of alpha-tocopherol transfer protein in rat brain.

Vitamin E (alpha-tocopherol) is a fat-soluble antioxidant that is transported by plasma lipoproteins in the body. Alpha-tocopherol transfer protein (alpha-TTP), which was identified as a product of the causative gene for familial isolated vitamin E (FIVE) deficiency, is a cytosolic liver protein which plays an important role in the efficient circulation of plasma vitamin E in the body. In the present study, we detected the message for alpha-TTP at low levels in some rat tissues including brain, spleen, lung and kidney. In the brain, the alpha-TTP transcript was detected predominantly in the cerebellar cortex, as revealed by in situ hybridization histochemistry. In the cerebellar cortex, clusters of the hybridization signal were aligned with the Purkinje cell layer, although the signal was not detected in the Purkinje cells, but in the small cells around the Purkinje cells. This distribution pattern strongly suggests that the message for alpha-TTP is expressed in the Bergmann glial cells. Combined with the previous observation that there was severe Purkinje cell loss in patients with FIVE deficiency, the present data suggest that vitamin E is supplied to the Purkinje cells from the surrounding Bergmann glial cells with the help of alpha-TTP.