title: Binding, internalization and degradation of colony-stimulating factor by peritoneal exudate macrophages.
abstract: Iodinated colony-stimulating factor produced by L-cells (125I-CSF-1) binds specifically to murine peritoneal exudate macrophages. At 37 degrees C, the cell-bound 125I-CSF-1 was internalized and degraded very rapidly, with the appearance of radioactive iodotyrosine in the medium. At 0 degree C, the cell-bound 125I-CSF-1 was not internalized and degraded, nor did it dissociate from the membrane. The internalization and degradation at 37 degrees C could be blocked or reduced by the presence of phenylglyoxal, methylamine and NH4Cl. The chemical nature of the CSF-1 binding site is polypeptide as judged by its sensitivity to trypsin treatment. After the binding and degradation of unlabeled CSF-1, the exudate cells were no longer able to rebind freshly added 125I-CSF-1, indicating the removal of CSF-1 binding site. The binding capacity of these cells, however, could be restored by prolonged incubation at 37 degrees C but not at 0 degrees C in culture medium containing fetal calf serum.
mesh_terms: D000818:Animals; D000963:Antimetabolites / Q000494:pharmacology; D001202:Ascitic Fluid / Q000378:metabolism; D001665:Binding Sites; D003115:Colony-Stimulating Factors / Q000378:metabolism*; D066298:In Vitro Techniques; D007739:L Cells / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008809:Mice, Inbred C3H; D013696:Temperature
chemical_list: D000963:Antimetabolites; D003115:Colony-Stimulating Factors