A comparison of serum retinol concentration between human and different species of normo and hypercholesterolemic nonhuman primates fed semi-purified diets with defined amounts of vitamin A

Abstract 1. 1. Serum retinol and total cholesterol concentrations were determined in several species of nonhuman primates fed semipurified diets. Two species of Old World and three species of New World nonhuman primates were examined. 2. 2. Retinol levels were significantly lower (up to four-fold) in the serum of the smaller New World than the larger Old World animals and the difference could not be explained by differences in dietary make-up. 3. 3. Cholesterol levels were not different between the groups but differed within a species when type of dietary fat was altered. 4. 4. Differences in circulating levels of retinol may reflect differences in levels of retinol binding protein between the groups.