title: Serum half-life and organ distribution of radiolabeled colony stimulating factor in mice.
abstract: Granulocyte-macrophage colony stimulating factor (GM-CSF) from mouse lung conditioned medium has recently been purified. This GM-CSF was radioiodinated using the chloramine T method, but dimethylsulfoxide was needed to prevent the loss of biological activity during the iodination. 125I-labeled GM-CSF was isolated from the reaction mixture by gel filtration and affinity chromatography with concanavalin A-Sepharose. One hour after intravenous injection of 125I-labeled GM-CSF almost 80% of the radioactivity was still localized in the serum. 125I-labeled GM-CSF was cleared from the blood of C57BL mice with a serum half-life of 7.3 +/- 1.3 hours. Six hours after intravenous injection 125I-GM-CSF appeared to be distributed throughout most of the tissues of C57BL mice. There was no selective concentration of 125I-labeled GM-CSF in the bone marrow, but levels in the kidney were three times higher than expected from the distribution of 125I-labeled mouse serum albumin. 125I detected in the blood 6 hours after injection of 125I-labeled GM-CSF was precipitable with trichloroacetic acid and bound to concanavalin A-Sepharose. 125I detected in the urine was not macromolecular and appeared to result from the degradation of 125I-labeled GM-CSF.
mesh_terms: D000818:Animals; D001826:Body Fluids / Q000032:analysis; D003115:Colony-Stimulating Factors / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D006098:Granulocytes; D006207:Half-Life; D007275:Injections, Intravenous; D007457:Iodine Radioisotopes; D008264:Macrophages; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D012711:Serum Albumin, Radio-Iodinated / Q000378:metabolism; D014018:Tissue Distribution
chemical_list: D003115:Colony-Stimulating Factors; D006023:Glycoproteins; D007457:Iodine Radioisotopes; D012711:Serum Albumin, Radio-Iodinated