A marginal vitamin A status alters the distribution of vitamin A among parenchymal and stellate cells in rat liver.

The aim of this study was to determine whether the distribution of vitamin A between parenchymal and stellate cells in rats with low vitamin A liver reserves is different from that observed in rats with adequate reserves. Retinol and retinyl esters were quantitated in parenchymal and stellate cells of the liver of three groups (n = 3) of adult Sprague-Dawley rats with mean total liver vitamin A reserves of 1.2, 14.5 and 28.9 micrograms retinol/g fresh liver for groups 1, 2 and 3, respectively. The amount of vitamin A per 10(6) cells was similar in parenchymal and stellate cells of group 1, whereas in groups 2 and 3, a much higher amount was found in stellate cells (11-fold and 27-fold higher, respectively). In group 1, 83% of the liver vitamin A was present in parenchymal cells. As liver stores rose, however, a progressively greater amount was stored in stellate cells. In group 3, 82% of the liver vitamin A was found in stellate cells. In groups 2 and 3, 87-91% of the vitamin A was found as retinyl ester, whereas in group 1, 52% was found as retinol. The retinyl ester composition was similar in parenchymal and stellate cells, major esters being palmitate (84%) and stearate (10%), with smaller amounts of oleate (2.5%) and other esters. Thus, in rats with low liver vitamin A reserves, most of the liver vitamin A is found in parenchymal cells.