Specific cellular responses to alpha-tocopherol

In the last 10 years precise cellular functions of alpha-tocopherol, some o f which are independent of its antioxidant/radical-scavenging ability, have been revealed. Absorption of alpha-tocopherol from the gut is a selective process. Other tocopherols are not absorbed or are absorbed to a lesser ext ent. At the post-translational level, alpha-tocopherol inhibits protein kin ase C and 5-lipoxygenase and activates protein phosphatase 2A and diacylgly cerol kinase. Some genes [platelet glycoprotein IV/thrombospondin receptor/ class B scavenger receptor (CD36), alpha-tocopherol transfer protein (alpha -TTP), alpha-tropomyosin, connective tissue growth factor and collagenase] are affected by alpha-tocopherol at the transcriptional level, alpha-Tocoph erol also inhibits cell proliferation, platelet aggregation, monocyte adhes ion and the oxygen burst in neutrophils. Other antioxidants, such as beta-t ocopherol and probucol, do not mimic these effects, suggesting a non-antiox idant, alpha-tocopherol-specific molecular mechanism.