Cellular localization of the receptor‐dependent and receptor‐independent uptake of human LDL in the liver of normal and 17α‐ethinyl estradiol‐treated rats

Abstract

The cellular localization in the liver of the receptor-dependent and -independent uptake of human low density lipoprotein (LDL) in normal and 17α-ethinyl estradiol-treated rats was investigated by the simultaneous in vivo injection of human ¹³¹I-LDL and human reductive methylated ¹²⁵I-LDL. The cells were subsequently isolated by a low temperature method. In untreated rats, after 30 min of in vivo circulation of human LDL, 57% of the receptor-dependent liver-association of human LDL occurs in non-parenchmal cells and 43% in parenchymal cells. Estradiol treatment of rats for 3 days selectively increases the receptor-dependent cell-association of human LDL with hepatocytes (17-fold), while the receptor-dependent cell-association with non-parenchymal cells is not affected.