Recent advances in vitamin E metabolism and deficiency
| Autor: | Ephrem Eggermont |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
medicine.medical_specialty
medicine.medical_treatment medicine.disease_cause Antioxidants Diagnosis Differential Terminology as Topic Internal medicine Gene expression Humans Vitamin E Medicine Vitamin E Deficiency heterocyclic compounds business.industry Nervous tissue food and beverages Metabolism medicine.disease medicine.anatomical_structure Endocrinology Pediatrics Perinatology and Child Health Hepatocytes Spinocerebellar ataxia lipids (amino acids peptides and proteins) Vitamin E deficiency business Oxidative stress Lipoprotein |
| Zdroj: | European Journal of Pediatrics. 165:429-434 |
| ISSN: | 1432-1076 0340-6199 |
| DOI: | 10.1007/s00431-006-0084-5 |
| Popis: | Alpha-, beta-, gamma- and delta-tocopherol are present in many foods and are, in the absence of fat malabsorption, well absorbed from the gut. Their anti-oxidant property is well known and protects arteries and capillaries as well as blood lipids and nervous tissue against oxidative stress. In contrast to beta-, gamma- and delta-tocopherol, alpha-tocopherol is preferentially conserved by the discriminating action of the liver alpha-tocopherol transfer protein, which also maintains plasma alpha-tocopherol concentration within a range of 20 to 40 microM. In the circulation, alpha-tocopherol, in association with the transfer-protein, is assembled into the very low-density lipoprotein and low-density lipoprotein particles and released for use by the peripheral tissues. Recent data suggest that alpha-tocopherol is not only an anti-oxidant but also a regulator of gene expression through its binding to nuclear receptors. The precise mechanism of regulating gene expression, however, is still unknown. The four tocopherols are ultimately degraded by omega-oxidation and subsequent beta-oxidations followed by the elimination of the metabolites in the bile and in the urine. Patients with a defect of the alpha-tocopherol transfer protein are unable to maintain their alpha-tocopherol reserves and progressively lose tendon reflexes and have signs and symptoms of spinocerebellar ataxia while plasma vitamin E level drops below 2 microg/ml. |
| Databáze: | OpenAIRE |
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