The effect of a non-absorbable fat on the turnover of plasma cholesterol in the rat.

Rats were injected with [4-14C]-cholesterol and then fed diets that contained sucrose polyester (SPE) at levels of 0 and 8% of the diet. 14C was measured in neutral and acidic steroid fractions of the feces collected during days 35-39 post i.v. injection. Periodic blood samples were used to measure the specific activity of the plasma cholesterol. The plasma data were consistent with a two-pool model for the decay of the plasma specific activity. The slow component of the decay curve decreased more rapidly in animals that received SPE. The half-life corresponding to this component was approximately 20% shorter in the SPE-fed animals compared to the control group. The mass of cholesterol calculated for the first pool was similar for all groups of animals. The 14C found in the feces was consistent with the more rapid removal of cholesterol from the body in the SPE-fed animals. The mass of excreted steroid was equal to the calculated rate of cholesterol production in each group of animals.