Influence of dietary vitamin E, selenium and age on regional distribution of alpha-tocopherol in the rat brain.
Concentrations of alpha-tocopherol (alpha-T) in plasma, cerebrum, cerebellum, midbrain and brain stem and activity of selenium (Se)-dependent glutathione peroxidase (GSH-Px) in plasma were measured in 1- and 15-month-old male F344 rats fed diets containing vitamin E (E, IU/kg) and Se (ppm) in the following combinations: 30 E, 0.1 Se (control diet, minimum requirements); 200 E, 0.2 Se; 0.0 E, 0.2 Se; 200 E, 0.0 Se; 0.0 E, 0.0 Se for 8 or 20 weeks. alpha-T and GSH-Px levels in plasma were reflective of dietary treatment in young rats in which an interaction of the two nutrients was noted. A longer period of dietary vitamin E deficiency was necessary to deplete plasma alpha-T and depress GSH-Px activity significantly in the old rats. Among the brain regions of all ages, cerebrum and midbrain had the highest concentrations of alpha-T while cerebellum showed the lowest. However, cerebellum of young rats and cerebellum and brain stem of old rats had a greater alpha-T accumulation with doubly supplemented diets, whereas only cerebellum of young and old rats showed a marked increase of alpha-T with vitamin E supplementation. In old rats, vitamin E deficiency resulted in greater depletion of alpha-T in cerebellum and brain stem than cerebrum and midbrain regions. Se deficiency in brain stem of young and old rats significantly decreased alpha-T accumulation by vitamin E supplementation. Se supplementation marginally alleviates vitamin E depletion in brain.(ABSTRACT TRUNCATED AT 250 WORDS)
D000375:Aging; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D005979:Glutathione Peroxidase / Q000097:blood; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344; D012643:Selenium / Q000494:pharmacology*; D014810:Vitamin E / Q000378:metabolism* / Q000494:pharmacology*; D014811:Vitamin E Deficiency / Q000378:metabolism*
D014810:Vitamin E; D005979:Glutathione Peroxidase; D012643:Selenium