Intestinal Absorption of Vitamin A in the Normal Rat

An Estimation of Plasma Vitamin A and the Vitamin A Absorption Test

“…Intermediate Absorption of Vitamin A Emmet and Bird (1937) suggested that the naturally occurring esters of vitamin A were better absorbed than the free alcohol by the rat. Gray, Morgareidge, and Cawley (1940), however, demonstrated in the same species that hydrolysis of the esters occurred and that the alcohol form was present in the mucosal cells of the intestine. Drummond, Bell, and Palmer (1935) observed that after feeding the free alcohol to a patient with a fistula of the thoracic duct the vitamin was recovered from the chyle mainly as an ester.…”

The Effects of Eating and of Sham Feeding Upon the Absorption of Vitamin a Palmitate in Man 1

“…In the case of vitamin A absorption, such tests have been performed either to study its assimilation as a vitamin, or as an indicator substance correlated more or less closely with the general absorption of fats. That vitamin A in oily solution is absorbed by man in a manner closely associated with the absorption of the oil in which it is dissolved, most studies would agree (1)(2)(3). When vitamin A acetate or palmitate or natural esters are given, dissolved in oil, the normal human subject exhibits an increase in the total vitamin A concentration of his blood serum for the succeeding 3 to 8 hours.…”

Serum studies in man after administration of vitamin A acetate and vitamin A alcohol: I In normal subjects

“…Vitamin A is absorbed in the upper small intestine as vitamin A alcohol, followed by reconversion to an ester before it reaches the circulation. The three main factors for its normal absorption are: 1, bile salts, 2, intestinal motility, and 3, pancreatic secretion (Gray, Morgareidge, and Cawley, 1940;Clausen, 1943). These factors are also necessary for the proper absorption of a neutral fat.…”