抄録
The extent of elevation in the serum cholesterol level in dietary cholesterol intake are varied among the subjects. In order to investigate the importance of the role of HDL to such variations of cholesterol elevation, following preliminary experiment has been performed. Five cases of healthy males without liver diseases, renal diseases and endocrine diseases, etc. were subjected. Six egg yolks daily (cholesterol value 1.5 grams) for seven days were administered to the subjects. Before and after the cholesterol loading, blood samples were drown from the subjects in the morning after the overnight fasting. Then, the serum concentrations of cholesterol, triglyceride, phospholipids and the three major lipoproteins classes (VLDL, LDL, HDL) have been determined.
One case in the subjects was with type V hyperlipoproteinemia. The remaining four cases were classified into two groups by the changes in serum HDL concentration after the cholesterol ingestion. The first group including two cases, in which serum HDL level increased after the cholesterol ingestion, showed small increase in serum cholesterol level and little change in VLDL and LDL levels. While, the second group in which serum HDL level decreased after the loading, revealed larger increases in both serum cholesterol and LDL levels than those of the first group.
From these results, it may be suggested that there exist two groups of subjects which show the differrent metabolic reaction under the dietary cholesterol administration. Namely, in the first group, the HDL level increases and reaches to the range of the normal value and the serum VLDL, LDL and cholesterol levels show little changes after cholesterol ingestion. In second group, the HDL level decreases and reaches to the normal range and the serum cholesterol and LDL levels elevated more than those of the first group after six egg yolks ingestion.
In the case of type V hyperlipoproteinemia in which serum HDL level was lower than that of normal subjects, decrease of HDL concentration and increase of LDL and VLDL concentrations were observed after the cholesterol administration.
Precise mechanism of above mentioned phenomenon is remained unknown. Further study should be required to investigate the mechanism.
