Effects of vitamin A and ascorbic acid on in vitro cholesterol biosynthesis in the rat
Elliott, J.G.; Lachance, P.A.
Journal of Nutrition 110(7): 1488-1496
1980
ISSN/ISBN: 0022-3166 PMID: 7381607 Document Number: 158246
Male rats were fed from weaning on a diet with vitamin A as retinyl acetate, none, 20, 436 or 6666 IU/g diet, and 2 ascorbic acid, none or 1 mg/g diet, for 28 days except for the largest amount of retinyl acetate which was given for only 3 days. The incorporation of [2-14C]mevalonic acid into cholesterol intermediates, fatty acids and bile acids was estimated in liver slices prepared from rats on those diets. Ascorbic acid synthesis was reduced in deficiency and excess of vitamin A; ascorbic acid in the diet prevented or blocked the decrease in liver ascorbic acid in vitamin A deficiency but not with most retinyl acetate. Retinyl acetate inhibited the incorporation of [2-14C]mevalonic acid into cholesterol, lanosterol, dimethylallyl alcohol, geranol and farnesol, but had no inhibitory effect on the incorporation into squalene, nerolidol or bile acids, and ascorbic acid had no inhibitory effect on cholesterol synthesis. There was no interaction between retinyl acetate and ascorbic acid.