Alpha and Gamma Tocopherols in Cerebrospinal Fluid and Serum from Older, Male, Human Subjects

Abstract

OBJECTIVE: The major forms of vitamin E in human physiological fluids are alpha and gamma tocopherols which exhibit different biological activities under a variety of assay conditions. The goal of this study was to obtain indirect information about the transport of tocopherols across the blood/spinal fluid barrier by comparing the concentrations of alpha and gamma tocopherols in serum and cerebrospinal fluid (CSF). METHODS: CSF and serum samples were obtained simultaneously from 28 human, male subjects excluding those with known pathology during the performance of spinal anesthesia procedures. The samples were centrifuged and frozen, and analyzed for tocopherols by HPLC with electrochemical detection. RESULTS: The concentrations of alpha and gamma tocopherols in CSF correlated significantly with their respective concentrations in serum. This would be expected since these nutrients have to be supplied by diet to serum followed by transport to the brain. The ratios of alpha to gamma tocopherols in the CSF and serum were highly correlated. High concentrations of alpha in serum tended to suppress gamma in both serum and CSF. CONCLUSIONS: These data suggest that the processes involved in the entry of tocopherol from blood to the CSF do not discriminate between the alpha and gamma tocopherols. In contrast, alpha tocopherol is highly preferred during the packaging of plasma lipoproteins by the liver. Our data also suggest that alpha and gamma tocopherols will be available to the human brain via transport from blood.