Abstract
An in vitro incubation procedure was established which enabled to estimate the cholesterol translocation between α- and β-lipoprotein regardless of TC levels in serum. This method is based on two principles. The first is the estimation of decrease of free cholesterol in β-lipoprotein fraction of sample serum; the decrease was calculated as the difference between the FC quantities in β-lipoprotein before incubation (βLpFC b. i.) and after incubation (βLpFC a. i.). The second is the esterification during incubation; the esterification arise only in α-lipoprotein particles. The EC quantity, transferred from α- to β-lipoprotein factors, was calculated as follow:
(αLpEC b. i.+EC e. d. i.)-αLpEC a. i. =EC (α→β) (LpEC stands for EC in α-lipoprotein, αLpEC a. i., for EC in α-lipoprotein after incubation, and EC e. d. i., for EC esterfied during incubation.)
The transfer of cholesterol was found to be influenced by factors such as follows: 1) LCAT activity, 2) cholesterol level, 3) triglyceride level, 4) imbalance of β-lipoprotein and α-lipoprotein, 5) imbalance of cholesterol and phospholipid, 6) ratio of βLpPL/αLpPL as well as Atherogenic-Index, and 8) age. In addition, some factors of unknown nature also appeared to influence the cholesterol transfer.
