Vitamin A contained in the lipid droplets of rat liver stellate cells is substrate for acid retinyl ester hydrolase.

Azaïs-Braesco, Véronique; Dodeman, Isabelle; Delpal, Serge,; Alexandre-Gouabau, Marie Cécile; Partier, Anne; Borel, Patrick,; Grolier, Pascal

Vitamin A contained in the lipid droplets of rat liver stellate cells is substrate for acid retinyl ester hydrolase.

1995

Vitamin A is stored in the lipid droplets of liver stellate cells (LSCs), as retinyl esters whose hydrolysis is necessary for the secretion of retinol into the blood. Here, we isolated these retinyl esters under their physiological form, i.e., in LSC lipid droplets, which had retained their morphological and biochemical characteristics. These retinyl esters are substrate for an hydrolytic enzyme, whose optimum pH is 4.1, and which is kinetically similar to the acidic retinyl ester hydrolase (aREH) we had previously described (Mercier et al., Biochim. Biophys. Acta (1994) 1212, 176-182). The cellular and subcellular localizations of aREH activity in rat liver suggest that this enzyme could be involved in the hydrolysis of the esterified vitamin A stores.

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