Comparative study in vivo and in vitro of uniformly 14C-labelled and 125I-labelled recombinant fibroblast growth factor 2.
Recombinant bovine fibroblast growth factor (FGF2), uniformly labelled with 14C ([14C]FGF2), was purified and showed to be highly stable and to retain full biological activity. Organ distribution of [14C]FGF2 after intravenous injection of young rats was assessed by autoradiography of whole body sections and compared with those obtained with [125I]iodinated FGF2 (125I-FGF2). Thyroid, stomach, intestine, bladder and skin were radioactively labelled only in the case of 125I-FGF2. This tissue-labelling is artefactual, probably due to free iodide binding not observed when using [14C]FGF2. High-resolution autoradiography showed a complex tissue distribution of [14C]FGF2 in kidney and adrenal organs. Incubation of frozen eye sections with [14C]FGF2 showed a specific and high-resolution labelling pattern of ocular tissues. After cellular internalization, [14C]FGF2 was processed into five distinct polypeptides of 16, 14, 8, 7, and 5.5 kDa. The 14-kDa and 7-kDa polypeptides are novel catabolic fragments not detected with radioiodinated FGF2. In terms of stability, tissue distribution specificity, and autoradiographic resolution, [14C]FGF2 proved to have more advantages than 125I-FGF2 for pharmacokinetic and catabolism studies.
Colin
S
S
Service de Biochimie et Génétique Moléculaire, CEA Saclay, Gif sur Yvette, France.
Mascarelli
F
F
Jeanny
J C
JC
Vienet
R
R
Bouche
G
G
Courtois
Y
Y
Labarre
J
J
D000311:Adrenal Glands / Q000378:metabolism; D000818:Animals; D001011:Aorta; D016477:Artifacts; D001345:Autoradiography; D001692:Biological Transport; D002250:Carbon Radioisotopes; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003001:Cloning, Molecular; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects; D005123:Eye / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000494:pharmacology; D006801:Humans; D007275:Injections, Intravenous; D007457:Iodine Radioisotopes; D007668:Kidney / Q000378:metabolism; D008297:Male; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000494:pharmacology; D013997:Time Factors; D014018:Tissue Distribution
D002250:Carbon Radioisotopes; D007457:Iodine Radioisotopes; D011994:Recombinant Proteins; D016222:Fibroblast Growth Factor 2