ISOMERIZATION OF VITAMIN A IN VIVO

Abstract

Pure all-trans and neovitamin A alcohol were administered orally to young, vitamin-A-deficient rats and the vitamin A and proportion of neovitamin A in the intestinal tract, liver and kidney were measured. In both cases considerable isomerization occurred in the stomach and the resulting mixture of isomers appeared to be absorbed by the intestine. The dose of all-trans vitamin A was taken up by the intestine more quickly than was the neovitamin A dose. An oral or subcutaneous dose of neovitamin A resulted in a relatively high proportion of neovitamin A in the liver but this proportion decreased during depletion to that found after a dose of all-trans vitamin A. The proportion of neovitamin A varied inversely with the size of dose of all-trans vitamin A and directly with the size of dose of neovitamin A. The significance of these results is discussed.