title: Radiolabeling of bombesin-like peptide with 99mTc: 99mTc-litorin and biodistribution in rats.
abstract: Bombesin-like peptides are related to several human cancer receptors, including small cell lung, prostate, breast, colon, and pancreatic cancers. Litorin, an amphibian bombesin peptide derivative, is found to stimulate the contraction of smooth muscle, to stimulate gastrin, gastric acid, and pancreatic secretion, and to suppress the nutriment in in vivo experiments. In the present study, litorin was labeled with 99mTc by the stannous chloride procedure. Labeling yield is 95 +/- 1.4%, as determined by radio thin layer chromatography (RTLC) and radio high performance chromatography (RHPLC). Results of in vitro studies demonstrated a high stability in serum and cysteine solutions. In vivo biodistribution was investigated with normal male Albino Wistar rats. Biodistribution data showed fast clearance, low intestinal accumulation, and significant uptake in bombesin/gastrin releasing peptide (BN/GRP) receptor rich tissues such as the pancreas (23.56 +/- 0.01 %ID/g 30 min pi). It can be blocked partially by previous administration of 'cold' litorin. The results showed specificity of the uptake. As 99mTc-litorin displays good radiolabeling and biodistribution, it is a potentially useful radiopharmaceutical for detection of bombesin receptor-expressing cancers.
authors.affiliation: Department of Nuclear Applications, Institute of Nuclear Sciences, Ege University, Bornova 35100, Izmir, Turkey.
authors.forename: Kubra
authors.initials: K
authors.lastname: Durkan
authors.forename: Fatma Yurt
authors.initials: FY
authors.lastname: Lambrecht
authors.forename: Perihan
authors.initials: P
authors.lastname: Unak
mesh_terms: D000818:Animals; D001839:Bombesin / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D003545:Cysteine / Q000737:chemistry; D007553:Isotope Labeling; D008297:Male; D009369:Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D009842:Oligopeptides / Q000737:chemistry* / Q000493:pharmacokinetics; D010455:Peptides / Q000737:chemistry*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000737:chemistry* / Q000493:pharmacokinetics; D051381:Rats; D017208:Rats, Wistar; D018004:Receptors, Bombesin / Q000378:metabolism; D017556:Technetium Compounds / Q000737:chemistry* / Q000493:pharmacokinetics; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured
chemical_list: D009842:Oligopeptides; D010455:Peptides; D019275:Radiopharmaceuticals; D018004:Receptors, Bombesin; D017556:Technetium Compounds; C010212:litorin; D003545:Cysteine; D001839:Bombesin