Cholesterol Kinetic Analyses in Normal and Cholesterol-fed Rabbits; Effects of Saturated Versus Polyunsaturated Fat and of Cholestyramine

Abstract

A model for cholesterol metabolism in rabbits has been demonstrated based on kinetic analysis and total carcass analysis. As has been shown for humans and primates, the model conforms to a two-exchangeable pool model with a third pool not exchangeing during the time interval studied. Alterations in turnover rate, sizes of pools, and exchange rates were demonstrated when rabbits were fed diets containing increased amounts of cholesterol and fat. Evidence was presented that indicated that the there may be differences in tissue distribution of cholesterol, dependent on whether the fat fed with choleserol is saturated or polyunsaturated. These differences include: in rabbits fed cholesterol plus coconut oil is compared with those fed cholesterol plus corn oil, the ratio of the amount of cholesterol in plasma to the amount of cholesterol in pool B was higher, and the rate constant for transfer from pool B was higher. The serum cholesterol concentration of rabbits fed cholesterol plus coconut oil was lowered slightly by feeding cholestyramine. Cholestyramine administration at the dose fed failed to produce statistically significant alterations in pool sizes or serum cholesterol concentration in control rabbits; it did lower serum cholesterol concentration in rabbits fed cholesterol plus coconut oil.