We investigated the possibility of the existence of hepatic Chylomicron Remnant (CR) receptors with HepG2 cells. In HepG2 cells incubated with LPDS or LPDS+25 OH cholesterol for 24 hours, the binding and internalization of 125I-CR were inhibited about 79.0% and 78.8% respectively by the incubation with unlabelled CR. On the other hand, in HepG2 cells incubated with LPDS or LPDS+25 OH cholesterol for 24 hours, the binding and internalization of 125I-CR were inhibited about 80.8% and 52.7% respectively by the incubation with unlabelled LDL. In human fibroblasts incubated with LPDS or LPDS+25 OH cholesterol for 24 hours, the bining and internalization of 125I-CR were inhibited about 79.7-82.4% and 73.7-78.6% by the incubation with unlabelled CR or unlabelled LDL. These results suggest that HepG2 cells may have functional remnant receptors which are not regulated by cholesterol loading.
