Abstract
To clarify the significance of apo E phenotypes on intermediate density lipoprotein (IDL) metabolism, the metabolism of IDL from the subjects with apo E phenotype E 2/2, E 3/2, E 4/7 or E 3/3 were studied by using rat isolated hepatocytes and rat peritoneal macrophages.
1) Binding of IDL with apo E 3/2 to isolated hepatocytes was almost the same as IDL with apo E 3/3. Uptake of IDL with apo E 3/2 into macrophages was the same as IDL with apo E 3/3.
2) Deficiency of binding to rat isolated hepatocytes was observed in IDL with apo E 2/2. Uptake of IDL with apo E 2/2 into macrophages was the same as IDL with apo E 3/3.
3) Binding of IDL with apo E 4/7 to isolated hepatocytes was about 80% of that of IDL with apo E 3/3. The cholesterol ester content in macrophages which were incubated with IDL with apo E 4/7 was increased by 1.7-fold compared with control macrophages which were incubated with IDL with apo E 3/3.
4) The binding activity of IDL, depending on apo E level, to isolated hepatocytes was diminished to 50% degree in apo E 3/2 compared to apo E 3/3.
5) Serum apo E level was inversely correlated to the binding activity of IDL, depending on apo E level, to isolated hepatocytes.
