We found that the binding of lzS1-low-density lipoprotein to fetal liver low-density lipoprotein receptor rose progressively with the increase in fetal age. During this period, total cholesterol and low-density lipoprotein-cholesterol levels in fetal serum declined significantly. The correlation coefficients between fetal age and concentration of serum total cholesterol and low-density lipoprotein cholesterol were -0.80 (p < 0.001) and -0.77 (p < 0.001), respectively. A significant inverse correlation also existed between the liver low-density lipoprotein receptor activity and the serum total cholesterol (r = -0.96, p < 0.001) and lowdensity lipoprotein cholesterol (r = -0.95, p < 0.001) but not high-density lipoprotein cholesterol. It is suggested that the low-density lipoprotein receptors in human fetal liver may play a key role in the regulation of the serum cholesterol levels during gestation. ( HEPATOLOGY 199 1; 13:852-857.)
The low-density lipoprotein (LDL) receptor is a surface membrane protein in diverse tissues of animals and humans. Plasma LDL, a cholesterol-rich lipoprotein, binds to this receptor and is taken into the cell by receptor-mediated endocytosis. The liver may account for as much as two thirds of the removal of LDL from blood stream in certain animal species and humans (1).