XXX CONTENTS 



(2) The Effect on Specific Tissues 680 



(3) Levels of Vitamin D Found Toxic 680 



XI. The Metabolism and Nutritional Value of the Vitamins E (Toco- 

 pherols) 683 



1 . Introduction 683 



2. Historical Development 684 



3. Occurrence of the Vitamins E 689 



( 1 ) Distribution in Plant Tissues 689 



(2) Distribution in Animal Tissues 691 



4. The Digestion and Absorption of the Tocopherols. . 697 



5. The Transport of Tocopherols from the Intestine to the Tissues 699 



6. The Metabolism of Absorbed Tocopherols 699 



(1) The Presence of Tocopherols in Blood 699 



(2) The Excretion of Absorbed Tocopherols 701 



(3) The Catabolism of Tocopherols 701 



7. The Importance of Tocopherols (Vitamins E) in Various Metabolic 



Processes 703 



(1) Introduction 703 



(2) The Function of the Tocopherols in the Metabolism of the Indi- 



vidual Foodstuffs 704 



a. Protein Metabolism 704 



(a) Efficiencj' of Protein Utilization 704 



(b) Creatinuria and Phosphocreatine 704 



(c) Myoglobinuria 705 



(d) Muscle Proteins 705 



(e) Allantoin 706 



b. Carbohydrate Metabolism 707 



(a) Pj-ruvic Acid Formation 707 



(b) Action on Cj^tochrome c Reductase 707 



(c) Effect on the Synthesis of Phosphoglucomutase 708 



(d) Effect on Glycogen and Blood Glucose 708 



c. Lipid Metabolism 709 



(a) Vitamin E Deficiencies Unrelated to Dietary F'at 710 



(b) Vitamin E Deficiencies Directly Related to Dietary Fat. . 711 



(c) Vitamin E Deficiencies Requiring Excessively Large 



Amounts of Unsaturated Fats 711 



d. Mineral Metabolism 711 



(3) The Importance of Tocopherols in Metabolism as Influenced B\^ 



Various Deficiency Symptoms 713 



a. Introduction 713 



b. The Acid-Fast Pigment Associated with Vitamin K Deficiency 713 



c. The Role of Vitamin E in Reproduction 714 



(a) Testioilar Degeneration in Avitaminosis E 714 



(b) Fetal Resorption in Avitaminosis E 716 



d. The Role of Vitamin E in Relation to Skeletal Muscle 718 



(a) Late-Lactation Paralysis 718 



