Evaluation of the Influence of the Conjugation Site of the Chelator Agent HYNIC to GLP1 Antagonist Radiotracer for Insulinoma Diagnosis.
OBJECTIVE
Radiotracer diagnosis of insulinoma, can be done using somatostatin or glucagon-like peptide 1 (GLP-1). Performance of GLP-1 antagonists tends to be better than of agonists.


METHODS
We investigated the uptake of the antagonist exendin (9-39), radiolabeled with technetium- 99m. Two different sites of the biomolecule were selected for chelator attachment.


RESULTS
HYNIC-βAla chelator attached to serine (C- terminus) of exendin, was associated with higher tumor uptake than to aspartate (N- terminus).


CONCLUSIONS
The chelator position in the biomolecule influenced receptor uptake.
Institute of Energy and Nuclear Research Radiopharmacy Center Av. Prof. Lineu Prestes, 2242 São Paulo, Brazil.
Bluma Linkowski
BL
Faintuch
Radiopharmacy Center, Institute of Energy and Nuclear Research, São Paulo, Brazil.
Daniele
D
Seo
Radiopharmacy Center, Institute of Energy and Nuclear Research, São Paulo, Brazil.
Erica Aparecida
EA
de Oliveira
Laboratory of Biopharmacology in Animal Cells, Butantan Institute, Sao Paulo, Brazil.
Roselaine Campos
RC
Targino
Laboratory of Biopharmacology in Animal Cells, Butantan Institute, Sao Paulo, Brazil.
Ana Maria
AM
Moro
D000818:Animals; D045744:Cell Line, Tumor; D002614:Chelating Agents / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D052216:Glucagon-Like Peptide 1 / Q000037:antagonists & inhibitors*; D007340:Insulinoma / Q000000981:diagnostic imaging*; D008297:Male; D051379:Mice; D016513:Mice, SCID; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging*; D010446:Peptide Fragments / Q000494:pharmacology*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000494:pharmacology*; D012680:Sensitivity and Specificity; D013667:Technetium / Q000494:pharmacology; D014018:Tissue Distribution
D002614:Chelating Agents; D010446:Peptide Fragments; D019275:Radiopharmaceuticals; C083773:exendin (9-39); D013667:Technetium; D052216:Glucagon-Like Peptide 1
GLP-1; Insulinoma; Technetium-99m; antagonist; exendin (9-39); radiotracer