VITAMINS 



375 



VITAMINS 



room with red light. Change to 70% 

 ale. and imbed in paraffin. Counter- 

 stain with "Kernechtrot" and light 

 green. 



For a description of the localization 

 of vitamin C in fibroblasts, during the 

 histogenesis of chick embryos, goblet 

 cells, Golgi apparatus, mitochondria, 

 etc. see Bourne, G., Cytology and Cell 

 Physiology, London: The Clarendon 

 Press, 1951, p. 262 et seq. 



D. The group of "vitamins D" consists 

 of a number of compounds (Rosenberg, 

 H. P., Chemistry and Physiology of the 

 Vitamins, New York: Interscience 

 Publishers, Inc., New York: 1942, 341 

 pp.) Di is a molecular compound con- 

 sisting of vitamin D2 and lumesterol. 

 D2-activated ergosterol, calciferol, or 

 viosterol. D3 is activated 7-dehydro- 

 cholesterol and D4 is activated 22- 

 dihydrocholesterol. D5 is activated 7- 

 dehydrositosterol . 



There are at least 10 provitamins D. 

 The vitamins D can be determined 

 chemically; but, since the methods are 

 based on conjugated unsaturation of 

 the vitamin D molecule, no distinction 

 between them can be made (Rosenberg, 

 1942, pp. 412-413). The biological 

 methods for the determination of vita- 

 mins D are reliable when properly 

 conducted and they are superior to 

 chemical and physical techniques. See 

 the Line Test. 



E. Antisterility vitamins of which there 

 are four: alpha, beta, delta and gamma 

 tocopherol. This vitamin can be de- 

 termined by chemical and biological 

 methods (Rosenberg, 1952, p. 452). 

 Vitamins E are also antioxidants, the 

 gamma isomer being more effective than 

 the beta isomer which, in turn, is more 

 effective than the alpha isomer which is 

 most active as the antisterility factor. 



A pigment, classified as a lipofuscin, 

 develops in the uterus of vitamin E 

 deficient rats (Elftman, H., Kaunitz, 

 H. and Slanetz, C. A., Annals N. Y. 

 Academy of Sciences, 1949, 52, 72-79). 

 This pigment probably arises from 

 the peroxidation and polymerization 

 of unsaturated fatty acids. Its ap- 

 pearance in the uterus can be pre- 

 vented by ovariectomy and by main- 

 taining the rats on a vitamin E-deficient 

 diet low in unsaturated fat (Atkinson, 

 W. B., Kaunitz, H. and Slanetz, C. A., 

 Ann., N. Y. Acad. Sci., 1949, 52, 68-71). 



Folic acid (pteroylglutamic acid, 

 vitamin Bo, factor U, L casei factor, 

 Norite eluate factor). A deficiency in 

 folic acids results in megaloblastic 

 arrest in the bone marrow and the de- 

 velopment of a macrocytic anemia. 

 In chicks it is necessary for normal 



growth, feathering, and egg hatchabil- 

 ity. For relationships between folic 

 acid and vitamin B^ see The Nutri- 

 tional and Chemical Significance of 

 Folic Acid, Lederle: American Cyana- 

 mid Co. 1950. 



F. A Vitagen, Essential fatty acids 

 consisting of linoleic, linolenic and 

 arachidonic. Arachidonic acid is phys- 

 iologically the most important com- 

 pound. 



H. Biotin (vitamin H, anti-egg-white 

 injury factor). Biotin can be assayed 

 microbiologically (Gyorgy, 1950, p. 

 61). It is probably a coenzyme for 

 oxalacetate decarboxylase involved in 

 the mechanisms of growth since its 

 content in embryonic and tumor tissue 

 is high. 



I. Inositol (mouse anti-alopecia factor). 

 This vitamin is hexahydroxy cyclohex- 

 ane. Its significance in human nutri- 

 tion has not yet been established. It 

 is present in relatively large amounts 

 in tissues and its occurrence as a unit 

 structure in lipids may later remove its 

 inclusion as a vitamin. Definite proof 

 that inositol acts catalytically has not 

 been obtained. 



K. The antihemorrhagic factor (phyllo- 

 quinone). 



Ki. is the first form of the antihemor- 

 rhagic vitamin isolated bv Dam, H., 

 Helv. Chem. Acta, 1939, 22, 310-313. 

 It is 2-methyl-3-phytyl-l,4-naphtho- 

 quinone. 



K2. is the second form isolated by 

 Brinkly, S. B., MacCorquodale, D. W., 

 Toyer, S. A., and Doisy, E. A., J. 

 Biol. Chem., 1939, 130, 219-234. It is 

 2 - methyl - 3 - difarnesyl - 1,4 - naptho- 

 quinone. Since the various K vitamins 

 are quinones, or easily oxidized to 

 quinones, most chemical methods pro- 

 posed for their determination are based 

 on oxidation-reduction titrations or 

 on color reactions utilizing the quinone 

 character of vitamin K (Gyorgy, 

 1950, p. 207, et seq.). 



Nicotinic acid (niacin, nicotin amide 

 and niacin amide). Microbiological 

 methods employing Lactobacillus arabi- 

 nosus 17-5, a yeast, Torula crernoris, 

 and a nonpathogenic bacterium, Pro- 

 teus H X 19, are more sensitive than 

 chemical methods (Williams, pp. 55- 

 56. The colorimetric methods which 

 have been widely used in nicotinic acid 

 assays all involve the interaction of 

 this vitamin with cyanogen bromide 

 and an aromatic amine (Williams, 1950, 

 p. 54). The coenzymes, diphosphopy- 

 ridine nucleotide and triphosphopyri- 

 dine nucleotide, contain nicotinic acid. 

 About forty different enzyme reactions 

 have been reported to be catalyzed by 



