Abstract

Background and 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).

Conclusion: The chelator position in the biomolecule influenced receptor uptake.

Keywords: Insulinoma, GLP-1, antagonist, exendin (9-39), radiotracer, Technetium-99m.

Graphical Abstract