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Department of Food Science, Rutgers University, New Brunswick, NJ 08903
In order to determine the effect of various doses of vitamin A and the interaction between vitamin A and ascorbic acid on cholesterol synthesis, male weanling rats were fed four levels of vitamin A as retinyl acetate (0, 20, 436 and 6,666 IU/g diet) and two levels of ascorbic acid (0 and 1 mg/g diet) for 28 days except the highest level of retinyl acetate which was fed for only 3 days. The incorporation of [2-14C]mevalonic acid into cholesterol intermediates, fatty acids and bile acids was determined in liver slices prepared from rats fed the above diets. The results may be summarized as follows: (a) ascorbic acid synthesis was reduced in both a deficiency and excess of vitamin A; (b) ascorbic acid in the diet prevented or blocked the decrease in liver ascorbic acid in vitamin A deficiency but not at the highest level of retinyl acetate (6,666 IU/g); (c) 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 (d) ascorbic acid had no inhibitory effect on cholesterol synthesis and no interaction between retinyl acetate and ascorbic acid was observed.
KEY WORDS: vitamin A ascorbic acid cholesterogenesis
1 This study was supported in part by a grant-in-aid from the Hoffman-La Roche Foundation, Nutley, NJ. A short abstract of this work has appeared (Elliott, J. G. & Lachance, P. A. (1977) Effect of vitamins A and C upon cholesterol biosynthesis in rat liver slices. Fed. Proc. 36, 1103 (abs. 4394).
2 Present address: Ralston Purina Co., Nutritional Laboratory, Central Research, Checkerboard Square, St. Louis, MO 63188.
Manuscript received 28 June 1979.