The utilization of intravenously administered carotene and vitamin A emulsion by rats and goats.

The utilization of intravenously administered aqueous dispersions of carotene has been investigated by a number of workers (e.g. Church, MacVicar, Bieri, Baker & Pope, 1954; Bieri & Pollard, 1954; Bieri, 1955; Kon, McGillivray & Thompson, 1955; McGillivray, Thompson & Worker, 1956), and it is now clearly established that carotene so administered can be converted into vitamin A in rats, rabbits, sheep and chicks. Further, to help interpret their findings with carotene dispersions, Kon et al. (1955) investigated the effect of injecting intravenously aqueous dispersions of vitamin A alcohol and ester and found that, despite rapid and considerable destruction of the vitamin A, a proportion of the dose was taken up by the liver and retained in an apparently normal manner. Owing, however, to the nature of the surface-active agent employed (Tween 40, polyoxyethylenesorbitan monopalmitate) these dispersions are highly unphysiological, and it seemed of interest to investigate the utilization of carotene and vitamin A emulsions prepared without the use of surface-active agents of this type and with the particle size of the dispersed fat phase of the same order as that of the blood chylomicrons.