US EPA

2456443 

Journal Article 

Serum is a rich source of ligands for the scavenger receptor on hepatic sinusoidal endothelial cells 

Hansen, B; Melkko, J; Smedsrod, B 

1999 

49-52 

WOS:000085097400017 

The present study was undertaken to characterize the substances in serum that effectively inhibit endocytosis via the hepatic sinusoidal endothelial cell (SEC) scavenger receptor (SR). Experiments with SEC in vitro showed that serum inhibits endocytosis of formaldehyde treated serum albumin and nidogen, that are ligands for the SR, by up to 80 %. Fractionation of serum on anion exchange and chromatofocusing chromatography revealed that the inhibitory substances are several highly negatively charged macromolecules of varying size. Endocytosis of non-SR ligands like mannan and collagen a-chains was not affected by fractionated serum. Intravenous injection of adduct-labelled fractionated serum revealed that the liver was the main site for elimination, and isolation of liver cells showed that SEC contained 75-80 % of liver radioactivity. Receptor specificity studies indicated that the negatively charged serum fraction was internalized mainly by the SEC SR.