Cholesterol Turnover and Metabolism in Normal and Hyperlipidemic Humans

Abstract

The turnover of plasma cholesterol has been studied extensively in recent years to provide information about the metabolism of cholesterol in normal subjects and in patients with hyperlipidemia and with obesity. In 1968, we reported (Goodman and Noble, 1968) that the plasma cholesterol specific radioactivity time curves obtained in experiments of about 10 weeks duration could be resolved into two exponential functions and, hence, that the turnover of plasma choiesterol conformed to a simple two-pool model. This model has been used extensively in many laboratories to study cholesterol turnover. In 1970, Samuel and Perl reported that in some patients the slow slope of the plasma decay curve deviated from monoexponential behavior after approximately 20–25 weeks. This suggested that a multicompartmental model of more than two pools was necessary to describe the long-term turnover of plasma cholesterol in man. The turnover of plasma cholesterol was subsequently studied by us for periods of 32–41 weeks in six subjects, and, in each subject, the best description of the turnover curve was found to be provided by a three-pool rather than a two-pool model (Goodman et al., 1973).