The Fat-Soluble Vitamins

The first demonstration of the existence of a vitamin and the full recognition of this fact are often attributed to the work of McCollum, who found that a sub stance in butterfat and cod-liver oil was necessary for growth and health of ani mals fed purified diets. It became obvious that an organic substance present in microconcentrations was vital to growth and reproduction of animals. Following the coining of the word vitamine by Funk, McCollum named this fat-soluble sub stance vitamin A. We can, therefore, state that vitamin A was certainly one of the first known vitamins, yet its function and the function of the other fat-soluble vitamins had remained largely unknown until recent years. However, there has been an explosion of investigation and new information in this field, which had remained quiescent for at least two or three decades. It is now obvious that the fat-soluble vitamins function quite differently from their water-soluble counter parts. We have learned that vitamin D functions by virtue of its being converted in the kidney to a hormone that functions to regulate calcium and phosphorus metabolism. This new endocrine system is in the process of being elucidated in detail, and in addition, the medical use of these hormonal forms of vitamin D in the treatment of a variety of metabolic bone diseases has excited the medical com munity.

Contenu
1 Vitamin A.- 1.1. Historical Developments in Vitamin A Research.- 1.2. Nomenclature and Chemistry.- 1.3. Biogenesis of Carotenoids.- 1.4. Conversion of ß-Carotene to Retinol.- 1.5. Retinoic Acid.- 1.6. The Visual Function.- 1.7. Isomers of Retinal.- 1.8. Bacteriorhodopsin of Halobacterium halobium.- 1.9. The Reproductive Function.- 1.10. Vitamin A and Bone.- 1.11. Introduction to the Epithelial Function.- 1.12. Retinyl Glycosides.- 1.13. Retinol-Binding Proteins.- 1.14. Binding Proteins in Tissues Other Than Blood.- 1.15. Vitamin A and Transformation.- 1.16. Conclusion.- 1.17. References.- 2 Vitamin D.- 2.1. Introduction.- 2.2. Historical.- 2.3. Absorption of Vitamin D.- 2.4. Production of Vitamin D in the Skin.- 2.5. Occurrence of Vitamin D Naturally.- 2.6. Structure and Physical Constants of the D Vitamins and Their Precursors.- 2.7. Vitamin D Deficiency.- 2.8. Vitamin D Metabolism.- 2.9. Regulation of Vitamin D Metabolism: Definition of the Vitamin D Endocrine System.- 2.10. Regulation of the Vitamin D System by the Need for Phosphorus..- 2.11. Regulation of Vitamin D Metabolism by the Sex Hormones and by Other Endocrine Systems.- 2.12. Mechanism of Action of l,25-(OH)2D3.- 2.13. Analogues of l,25-(OH)2D3.- 2.14. Toxicity of Vitamin D.- 2.15. Vitamin D Metabolism and Disease.- 2.16. Conclusion.- 2.17. References.- 3 Vitamin E.- 3.1. Introduction.- 3.2. History.- 3.3. Chemistry of Vitamin E.- 3.4. Deficiency Diseases.- 3.5. Metabolic Roles of Vitamin E.- 3.6. Vitamin E Requirements.- 3.7. Sources of Vitamin E.- 3.8. Methods of Assay.- 3.9. Absorption, Transport, and Storage of Vitamin E.- 3.10. High Dietary Intakes of Vitamin E.- 3.11. Conclusions.- 3.12. References.- 4 Vitamin K.- 4.1. Introduction.- 4.2. Biological Activity and Physiology.- 4.3. Metabolism.- 4.4.Dietary Requirement.- 4.5. Antagonists of Vitamin Action.- 4.6. Metabolic Role of Vitamin K.- 4.7. Non-Clotting-Factor Role of Vitamin K.- 4.8. Conclusion.- 4.9. References.