In vivo inflammatory stimulation induces a transient change in the binding of thrombin to rat peritoneal macrophages.
The binding of 125I-labeled thrombin to rat peritoneal macrophages isolated 20 h after the ip injection of thioglycollate broth or lipopolysaccharide decreased to 20% of the value found in resident macrophages due to a decrease in the number of receptors. The binding returned to normal values within a week after the injection. The decline parallelled more or less the Vmax for the 5'-nucleotidase activity. This decrease in the binding of thrombin could not be explained by an immigration of monocytes into the peritoneal cavity, since the binding of 125I-labeled alpha 2-macroglobulin-trypsin complex increased 4.5-fold in the same cell population due to an increase in the number of receptors, and blood monocytes do not bind alpha 2-macroglobulin-trypsin complex. The increase in the binding of alpha 2-macroglobulin-protease complex parallelled an increase in the incorporation of glucosamine, although the latter did not increase to the same extent. Engulfment of plasma membrane after phagocytosis did not result in a decreased binding of thrombin, but preincubation at 37 degrees C with concanavalin A caused a minor reduction in the binding. There was a positive correlation between the binding of alpha 2-macroglobulin-trypsin complex and the fraction of polymorphonuclear leukocytes in the peritoneal exudate and a negative correlation between the binding of thrombin and the fraction of polymorphonuclear leukocytes in the exudate, when the inflammation was induced by a milder stimulus, sterile NaCl, indicating a common signal for the polymorphonuclear leukocyte chemotaxis and the macrophage differentiation.
Fisker
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S
Institute of Physiology, University of Aarhus, Denmark.
Kudahl
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K
Sonne
O
O
D000818:Animals; D002478:Cells, Cultured; D007249:Inflammation / Q000139:chemically induced / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000633:toxicity*; D008262:Macrophage Activation; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D010529:Peritoneal Cavity / Q000166:cytology; D011485:Protein Binding / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000187:drug effects; D018179:Receptors, Thrombin; D013864:Thioglycolates / Q000494:pharmacology*; D013917:Thrombin / Q000378:metabolism*
D008070:Lipopolysaccharides; D011956:Receptors, Cell Surface; D018179:Receptors, Thrombin; D013864:Thioglycolates; D013917:Thrombin