Vitamin A induced hypertriglyceridemia in cholesterol-fed rats

The effects of level and feeding frequency of retinoic acid (OIC) or retinyl acetate (YL) on the accumulation of lipids in the serum and liver of rats were investigated. Male Sprague-Dawley rats were fed ad libitum 1% cholesterol diets with or without supplemental OIC or YL. Vitamin A-fed groups included (per g of dry diet): 105 microgram of OIC or 113 microgram YL daily for 28 days, 735 microgram OIC or 791 microgram YL once each week for 28 days; and 735 or 105 microgram OIC on day 1 or 105 microgram OIC daily for the week experiment. Daily feeding of OIC or YL increased serum triglyceride concentrations as compared to conrols. Several days after removal of OIC or 1 week after removal of supplemental YL from the rat diets, serum triglyceride concentrations returned to basal levels. Cholesterol feeding elevated serum cholesterol as well as hepatic cholesterol, total lipids and vitamin A concentrations. Daily OIC feeding depressed serum and hepatic cholesterol concentrations. These results show that daily supplement of vitamin A increased serum triglycerides and reduced serum and hepatic cholesterol concentrations. Serum and liver alterations were dependent on continued feeding.