Vitamin A in parenteral nutrition: uptake and distribution of retinyl esters after intravenous application.

Short-term parenteral application of vitamin A was examined in rats. Retinyl margarinate, which is chemically similar to physiological retinyl esters, was used in vitamin A-depleted rats to study uptake, distribution, and storage of retinyl esters in tissues. Vitamin A-depleted and Vitamin A-sufficient rats were infused with a micellar suspension of retinyl margarinate for 7 h and then killed at different times. Retinyl margarinate was directly taken up by all tissues examined. It appears that infusion of retinyl esters in micellar form provides a direct way to supply vitamin A to peripheral, vitamin A-dependent tissues. Therefore, a short-term infusion of retinyl esters with an emulsifier may be an effective means of preventing development of vitamin A-deficiency during long-term application of TPN, particularly in cases of liver dysfunction.