Total body turnover of
cholesterol was studied in two patients with
abetalipoproteinemia, a 32-year-old man and a 31-year-old woman. The patients received [14C]
cholesterol intravenously, and the resulting specific activity-time curves (for 40 and 30 weeks, respectively) were fitted with a three-pool model. Parameters were compared with those from studies of
cholesterol turnover in 82 normal and hyperlipidemic subjects. A three-pool model gave the best fit for the abetalipoproteinemic patients, as well as for the 82 previously studied subjects, suggesting general applicability of this model.
Cholesterol production rates in the two abetalipoproteinemic subjects (0.82 and 0.89 g/day) were close to values predicted for persons of their
body weight. Thus, total body turnover rate of
cholesterol was quite normal in
abetalipoproteinemia, confirming previous reports. Very low values (9.2 and 8.4 g) were found for M1, the size of the rapidly exchanging compartment pool 1, in the two abetalipoproteinemic subjects. These values were well below the values predicted (from the comparison study population) for normal persons of this size with low plasma
cholesterol levels. For one patient, total body exchangeable
cholesterol was very low, although not significantly below the predicted values for a person of his size. In the second patient, the observed estimate for total body exchangeable
cholesterol was well within the range of values predicted for persons of her size with low to extremely low
cholesterol levels.(ABSTRACT TRUNCATED AT 250 WORDS)