Studies on metabolism of vitamin A. 8. Effect of ascorbate on isoprenoid metabolism in vitamin A-deficient rats

Abstract

The effect of the administration of ascorbate on isoprenoid metabolism in vitamin A-deficient rats was studied. The administration of ascorbate to vitamin A-deficient rats led to a lowered synthesis of ubiquinones in the livers compared with that in the livers of ascorbate-deprived vitamin A-deficient animals. The incorporation of [2-C14] mevalonate into the sterols was higher and that into the squalene and ubiquinone fractions lower in the ascorbate-supplemented vitamin A-deficient animals, when compared with those in the ascorbate-deprived vitamin A-deficient rats. Liver preparations in vitro from ascorbate- supplemented vitamin A-deficient rats showed increased incorporation of [2-C14] mevalonate into the unsaponifiable materials, with greater radioactivity in the sterol fraction than in the squalene fraction, as compared with the ascorbate-deprived vitamin A-deficient rats. The addition of vitamin A alcohol or acid or ascorbate had no effect.