摘要：The uptake of fractionated heparin was examined in the absence and presence of anionic proteins such as acetylated low density lipoprotein (Ac-LDL) and maleylated bovine serum albumin (Mal-BSA) to characterize the scavenger receptors involved in the uptake of fractionated heparin in isolated rat Kupffer cells. The uptake of fractionated heparin was completely inhibited by Ac-LDL and dextran sulfate, but only partially by Mal-BSA.Kinetic analysis revealed that the binding capacity (Bmax) of the Mal-BSA-insensitive receptor was significantly larger than that of the Mal-BSA-sensitive one, though their dissociation constants (Kd) were not significantly different. The apparent internalization rate constant (kint, app) was significantly larger for the Mal-BSA-sensitive receptor than for the Mal-BSA-insensitive one. Thus, the scavenger receptors involved in the uptake of fractionated heparin in Kupffer cells can be classified into two types, in terms of sensitivity to Mal-BSA. Mal-BSA-sensitive receptors have been characterized in macrophages and classified as class A. The Mal-BSA-sensitive one found in Kupffer cells in this study may belong to class A, while the Mal-BSA-insensitive one has been little characterized elsewhere.
关键词：fractionated heparin;scavenger receptor;Kupffer cell;maleylated bovine serum albumin;acetylated low density lipoprotein
