The fate of intracardially administered retinyl esters in the rat

Abstract

Rats with very low liver reserves of vitamin A were intracardially injected with Tween 20 dispersions of retinol, retinal, retinyl acetate, retinyl laurate, retinyl myristate, retinyl palmitate, retinyl stearate or retinyl linoleate. Blood, liver and lungs were analysed for retinol and its various esters at different time-intervals from 5 min. to 24 hr. after the injections. When retinol, retinal or retinyl palmitate was injected, the rat tissues contained no other ester of retinol but the palmitate. With the other esters, although small amounts could be detected in blood and liver immediately after the injection, after 6 hr. only one ester, the palmitate, was deposited in the liver. The possible mechanisms determining the specificity of the formation and storage of the palmitate are discussed.