Chapter 6 

 VITAMIN D GROUP 



Page 



I. Nomenclature and Formulas 132 



II. Chemistry 132 



A. The Sterols 133 



B. The Provitamin Theory and Syntheses 138 



1. History 138 



2. Syntheses 140 



3. Chemical Structure and Activatabilitj' 143 



4. Newer Synthetic Methods 146 



C. The Provitamins D in Nature 148 



1. Isolation 148 



2. Ergosterol 153 



3. 7-Dehydrooholesterol 154 



4. Provitamins D of Invertebrates 155 



5. Biogenesis 156 



D. The Vitamins D 160 



1. Occurrence and Origin 160 



2. Isolation from Natural Sources 172 



3. Physics of Activation 173 



4. Chemistry of Activation 179 



5. Minor and Obscure Forms 203 



III. Industrial Preparation 210 



IV. Estimation 215 



A. Physical Methods 215 



B. Chemical Methods 216 



C. Biological Methods 218 



V. Standardization of Activity 221 



VI. Effects of Deficiency 223 



A. In Animals 223 



1. External Appearance _4 224 



2. Growth 225 



3. Calcium and Phosphorus of the Serum 225 



4. Blood Phosphatase 226 



5. X-Ray Examination 227 



6. Calcium and Phosphorus Balance 228 



7. Acidity of Intestinal Contents 229 



8. Bone Ash 230 



9. Histological Changes in the Ricketic Bone 231 



B. In Pathology of Human Beings 232 



VII. Chemical Pathology and Pharmacology 248 



VIII. Requirements 253 



A. Of Animals 253 



B. Of Human Beings 257 



1. Hypervitaminosis D 264 



131 



