Effect of chronic administration of excess dietary vitamin A and zinc on lipid metabolism in rats.
The effects of chronic feeding of excess dietary vitamin A and zinc on serum cholesterol, liver cholesterol and total liver lipids were studied in rats. Sixty-four Sprague-Dawley female rats were randomly allocated to 4 groups: basal diet: 4848 micrograms of vitamin A and 61 mg of Zn/kg of diet; high Zn (33-fold excess of the requirement) + basal vitamin A; basal Zn + high vitamin A (154-fold excess of the requirement) and high Zn + high vitamin A. After 120 days serum cholesterol, liver cholesterol, total liver lipids, and vitamin A and zinc in the liver and kidney were measured. The mean serum cholesterol (+/- SE) for the 4 groups were: 121 (+/- 12.6), 159 (+/- 6), 133 (+/- 7.6) and 186 (+/- 7.6) mg/dl, respectively. Liver cholesterol and total lipids for the 4 groups were determined as 1.8 (+/- 0.05), 2.2 (+/- 0.09), 4.9 (+/- 0.12) and 4.6 (+/- 0.24) mg/g of tissue and 26.3 (+/- 0.7), 26.0 (+/- 1.1), 38.9 (+/- 0.9) and 40.3 (+/- 1.4) mg/g of tissue, respectively. Liver and kidney vitamin A levels were significantly higher in group C than in group D, suggesting increased vitamin A metabolism in the high dietary zinc + high vitamin A groups. In high dietary zinc groups, a significant elevation of serum cholesterol was observed regardless of the vitamin A levels. Total liver lipids and liver cholesterol were significantly higher in rats fed high vitamin A irrespectively of the zinc levels in the diet.
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002784:Cholesterol / Q000378:metabolism; D004032:Diet; D004435:Eating / Q000187:drug effects; D005260:Female; D007668:Kidney / Q000378:metabolism; D050356:Lipid Metabolism; D008099:Liver / Q000378:metabolism; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D014801:Vitamin A / Q000008:administration & dosage* / Q000378:metabolism; D015032:Zinc / Q000008:administration & dosage* / Q000378:metabolism
D014801:Vitamin A; D002784:Cholesterol; D015032:Zinc