title: Tissue distribution of recombinant human tumor necrosis factor alpha derivative in mice.
abstract: OBJECTIVE
  To study the tissue distribution and its mechanism of a new recombinant tumor necrosis factor alpha derivative (rhTNF alpha Da) in mice.
  
  
  METHODS
  125I-rhTNF alpha Da was prepared by Iodogen method. Tissue distribution of 125I-rhTNF alpha Da in mice was studied by determining radioactivity of tetrachloroacetic acid (TCA)- precipitable fraction in tissues. The isolated heart-lung perfusion study using 125I-rhTNF alpha Da perfusate was carried out to study the distribution characteristics of 125I-rhTNF alpha Da in lung.
  
  
  RESULTS
  Except for thyroid, AUC of the TCA-precipitable 125I-rhTNF alpha Da in tissues was highest in lung, which was 12.2-fold of that in serum, while concentrations in other tissues were all lower than that in serum. Perfusion study in vitro revealed that the concentration of radio-labeled peptide in lung was higher than that in perfusate. On the contrary, level in heart was much lower than that in perfusate. The overall distribution of 125I-rhTNF alpha Da in lungs showed rapidly equilibratory, dose-dependent, saturable, competitive, and highly affinitive, with Kd 47.6 pmol.L-1 and Bmax 348 fmol.g-1 (lung tissue).
  
  
  CONCLUSIONS
  The specific distribution of rhTNF alpha Da in lungs was its distinctive characteristics.
authors.affiliation: Department of Pharmacology, Institute of Radiation Medicine, Beijing, China.
authors.forename: B X
authors.initials: BX
authors.lastname: Chai
authors.forename: Z M
authors.initials: ZM
authors.lastname: Tang
authors.forename: X W
authors.initials: XW
authors.lastname: Liu
authors.forename: M
authors.initials: M
authors.lastname: Tu
mesh_terms: D000818:Animals; D005260:Female; D008168:Lung / Q000378:metabolism; D008297:Male; D051379:Mice; D009206:Myocardium / Q000378:metabolism; D011897:Random Allocation; D011994:Recombinant Proteins / Q000493:pharmacokinetics; D014018:Tissue Distribution; D014409:Tumor Necrosis Factor-alpha / Q000493:pharmacokinetics*
chemical_list: D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha