Characterization of the interaction of a complex of tissue-type plasminogen activator and plasminogen activator inhibitor type 1 with rat liver cells.

The present study was undertaken in order to determine the recognition site for tissue-type plasminogen activator-plasminogen activator inhibitor type 1 [t-PA-PAI-1] complexes in rat liver in vivo and in vitro. After intravenous injection into rats t-PA-PAI-1 complexes were rapidly removed from the plasma and the liver took up 80% of the injected dose. Within the liver parenchymal and endothelial liver cells contributed mainly to the uptake of t-PA-PAI-1, and were responsible for 62% and 24% of the liver uptake, respectively.

Zonal distribution of receptor binding of trypsin-activated alpha 2-macroglobulin, alpha 2-macroglobulin receptor-associated protein, lactoferrin and transferrin on rat liver parenchymal cells.

Periportal and perivenous rat liver parenchymal cells were isolated according to the digitonin-collagenase perfusion method. Affinities and maximal specific binding of a conjugate of glutathione S-transferase and the alpha 2-macroglobulin receptor-associated protein (GST-39kDaP), of lactoferrin and of transferrin to freshly isolated periportal parenchymal cells in vitro were not significantly different from values obtained with perivenous cells. It is concluded that the receptors for these three ligands show a zonally homogeneous expression in rat liver.

Different zonal distribution of the asialoglycoprotein receptor, the alpha 2-macroglobulin receptor/low-density-lipoprotein receptor-related protein and the lipoprotein-remnant receptor of rat liver parenchymal cells.

Periportal and perivenous parenchymal cells were isolated by the digitonin-pulse perfusion method. The digitonin-pulse perfusion was shown to lead to selective lysis of the correct zone with a straight and sharp border of two to three cells. The mean ratios of alanine aminotransferase activity (a marker for periportal parenchymal cells) and glutamine synthetase activity (a perivenous marker) of periportal to perivenous parenchymal cells were 1.