Plasma clearance, organ distribution and target cells of interleukin-6/hepatocyte-stimulating factor in the rat.
The plasma half-life of recombinant human interleukin-6 (rhIL-6) was determined in rats by measuring the disappearance of the biological activity as well as of the radioactivity of 125I-rhIL-6 from the circulation. The kinetics of clearance were biphasic. It consisted of a rapid initial disappearance corresponding to a half-life of 3 min, and of a second slow one corresponding to a half-life of about 55 min. By cellulose-acetate electrophoresis it was shown that rhIL-6 binds to a plasma protein resulting in a complex migrating in the beta-gamma region; 20 min after intravenous injection, about 80% of the 125I-rhIL-6 that had disappeared from the circulation was found in the liver. 125I-rhIL-6 was exclusively localized on the surface of parenchymal cells suggesting the existence of an interleukin-6 receptor on the hepatocytes.
Castell
J V
JV
Biochemisches Institut, Universität Freiburg, Federal Republic of Germany.
Geiger
T
T
Gross
V
V
Andus
T
T
Walter
E
E
Hirano
T
T
Kishimoto
T
T
Heinrich
P C
PC
D000818:Animals; D001345:Autoradiography; D001798:Blood Proteins / Q000378:metabolism; D004588:Electrophoresis, Cellulose Acetate; D004591:Electrophoresis, Polyacrylamide Gel; D006207:Half-Life; D015850:Interleukin-6; D007378:Interleukins / Q000493:pharmacokinetics*; D007457:Iodine Radioisotopes; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011971:Receptors, Immunologic / Q000378:metabolism; D019947:Receptors, Interleukin-6; D011994:Recombinant Proteins / Q000493:pharmacokinetics*; D014018:Tissue Distribution
D001798:Blood Proteins; D015850:Interleukin-6; D007378:Interleukins; D007457:Iodine Radioisotopes; D011971:Receptors, Immunologic; D019947:Receptors, Interleukin-6; D011994:Recombinant Proteins