Feedback regulation of metabolism by dietary constituents: lipids

Cholesterol is distributed in different body pools, Input in these pools takes place through absorption of dietary cholesterol and endogenous synthesis. Absorption is limited in man. Endogenous synthesis is under negative feedback control, but its physiological relevance in man is less well established. Recent studies in familial hypercholesterolemia have shown a slower catabolism of low density lipoproteins (LDL) and an overproduction of apoprotein B. It seems that also the synthesis of the apoprotein B is controlled by a feedback mechanism. Overall concentration of lipids and lipoproteins in plasma is determined by the interaction between several genetic and dietary feedback mechanisms.

Turnover of cholesteryl esters in plasma low-density and high-density lipoproteins in familial hyperbetalipoproteinaemia

1. The turnover of cholesteryl esters in plasma high-density (HDL) and low-density (LDL) lipoproteins was measured in patients with familial hyperbetalipoproteinaemia in the homozygous and heterozygous forms and in control subjects.

2. The fractional rates of turnover of HDL and LDL cholesteryl esters were significantly lower in the patients than in the control subjects, but there was no significant difference between the absolute rates of turnover (expressed in mg h−1 kg body wt.−1) in the patients and controls.