PROPERTIES OF VITAMINS A AND RELATED COMPOUNDS 



737 



anhydrovitamin A is comertcd in. vivo to a c*()m})ouiKl liaving al)out 20 

 times the biological activity of the original substance. He named this 

 compound "rehydrovitamin A" because a Avater molecule was added. 

 After anhydrovitamin A is fed to vitamin-A-deficicnt rats for 3 weeks, the 

 new compound can be isohiled from lii(> liver; no anhydrovitamin A is 

 found to be stored as such under these conditions. The new compound 

 produces a blue color with antimony trichloride having a maximum at ()12 

 m^. Shantz^''' has suggested that the new vitamin derivative is an isomer 

 of vitamin A with the structure shown here. 



CHoOH 



Reh>-drovitamin A 



250 300 350 400 



WAVELENGTH myu 



450 



Fig. 9. Ultraviolet absorption spectra of rehydrovitamin A in ethanol: 

 (/) 0.152% solution of .saponified liver oil extract from rats fed anhydro- 

 vitamin A; {2) 0.0008% solution of crystalline vitamin A alcohol; {3) 

 0.00044% .solution of crystalline anhydrovitamin A.^^^ 



In explaining the bio.synthesis of rehydrovitamin A, Shantz conjectured 

 that the vitamin-A-deficient animal, in the attempt to utilize anhydrovita- 

 min A, is able to add the elements of water to a small proportion of the 



